Merge pull request #1032 from kiwix/error_response_i18n

Translation of error pages

src/server/i18n.cpp

@@ -112,8 +112,12 @@ std::string expandParameterizedString(const std::string& lang,
                                       const std::string& key,
                                       const Parameters& params)
 {
+  kainjow::mustache::object mustacheParams;
+  for( const auto& kv : params ) {
+    mustacheParams[kv.first] = kv.second;
+  }
   const std::string tmpl = getTranslatedString(lang, key);
-  return render_template(tmpl, params);
+  return render_template(tmpl, mustacheParams);
 }
 
 } // namespace i18n

src/server/i18n.h

@@ -20,6 +20,7 @@
 #ifndef KIWIX_SERVER_I18N
 #define KIWIX_SERVER_I18N
 
+#include <map>
 #include <string>
 #include <mustache.hpp>
 
@@ -44,7 +45,7 @@ std::string getTranslatedString(const std::string& lang, const std::string& key)
 namespace i18n
 {
 
-typedef kainjow::mustache::object Parameters;
+typedef std::map<std::string, std::string> Parameters;
 
 std::string expandParameterizedString(const std::string& lang,
                                       const std::string& key,
@@ -93,10 +94,10 @@ private:
 
 } // namespace i18n
 
-struct ParameterizedMessage
+class ParameterizedMessage
 {
 public: // types
-  typedef kainjow::mustache::object Parameters;
+  typedef i18n::Parameters Parameters;
 
 public: // functions
   ParameterizedMessage(const std::string& msgId, const Parameters& params)
@@ -106,6 +107,9 @@ public: // functions
 
   std::string getText(const std::string& lang) const;
 
+  const std::string& getMsgId()  const { return msgId; }
+  const Parameters&  getParams() const { return params; }
+
 private: // data
   const std::string msgId;
   const Parameters  params;

src/server/internalServer.cpp

@@ -513,6 +513,19 @@ static MHD_Result staticHandlerCallback(void* cls,
                                 cont_cls);
 }
 
+namespace
+{
+
+MHD_Result add_name_value_pair(void *nvp, enum MHD_ValueKind kind,
+                               const char *key, const char *value)
+{
+  auto& nameValuePairs = *reinterpret_cast<RequestContext::NameValuePairs*>(nvp);
+  nameValuePairs.push_back({key, value});
+  return MHD_YES;
+}
+
+} // unnamed namespace
+
 MHD_Result InternalServer::handlerCallback(struct MHD_Connection* connection,
                                            const char* fullUrl,
                                            const char* method,
@@ -529,7 +542,10 @@ MHD_Result InternalServer::handlerCallback(struct MHD_Connection* connection,
   }
 
   const auto url = fullURL2LocalURL(fullUrl, m_rootPrefixOfDecodedURL);
-  RequestContext request(connection, m_root, url, method, version);
+  RequestContext::NameValuePairs headers, queryArgs;
+  MHD_get_connection_values(connection, MHD_HEADER_KIND, add_name_value_pair, &headers);
+  MHD_get_connection_values(connection, MHD_GET_ARGUMENT_KIND, add_name_value_pair, &queryArgs);
+  RequestContext request(m_root, url, method, version, headers, queryArgs);
 
   if (m_verbose.load() ) {
     request.print_debug_info();
@@ -926,7 +942,8 @@ std::unique_ptr<Response> InternalServer::handle_search_request(const RequestCon
     HTTPErrorResponse response(request, MHD_HTTP_NOT_FOUND,
                                "fulltext-search-unavailable",
                                "404-page-heading",
-                               cssUrl);
+                               cssUrl,
+                               /*includeKiwixResponseData=*/true);
     response += nonParameterizedMessage("no-search-results");
     // XXX: Now this has to be handled by the iframe-based viewer which
     // XXX: has to resolve if the book selection resulted in a single book.

src/server/request_context.cpp

@@ -51,11 +51,12 @@ RequestMethod str2RequestMethod(const std::string& method) {
 
 } // unnamed namespace
 
-RequestContext::RequestContext(struct MHD_Connection* connection,
+RequestContext::RequestContext(const std::string& _rootLocation, // URI-encoded
-                               const std::string& _rootLocation, // URI-encoded
                                const std::string& unrootedUrl,   // URI-decoded
                                const std::string& _method,
-                               const std::string& version) :
+                               const std::string& version,
+                               const NameValuePairs& headers,
+                               const NameValuePairs& queryArgs) :
   rootLocation(_rootLocation),
   url(unrootedUrl),
   method(str2RequestMethod(_method)),
@@ -64,9 +65,13 @@ RequestContext::RequestContext(struct MHD_Connection* connection,
   acceptEncodingGzip(false),
   byteRange_()
 {
-  MHD_get_connection_values(connection, MHD_HEADER_KIND, &RequestContext::fill_header, this);
+  for ( const auto& kv : headers ) {
-  MHD_get_connection_values(connection, MHD_GET_ARGUMENT_KIND, &RequestContext::fill_argument, this);
+    add_header(kv.first, kv.second);
-  MHD_get_connection_values(connection, MHD_COOKIE_KIND, &RequestContext::fill_cookie, this);
+  }
+
+  for ( const auto& kv : queryArgs ) {
+    add_argument(kv.first, kv.second);
+  }
 
   try {
     acceptEncodingGzip =
@@ -83,18 +88,14 @@ RequestContext::RequestContext(struct MHD_Connection* connection,
 RequestContext::~RequestContext()
 {}
 
-MHD_Result RequestContext::fill_header(void *__this, enum MHD_ValueKind kind,
+void RequestContext::add_header(const char *key, const char *value)
-                                       const char *key, const char *value)
 {
-  RequestContext *_this = static_cast<RequestContext*>(__this);
+  this->headers[lcAll(key)] = value;
-  _this->headers[lcAll(key)] = value;
-  return MHD_YES;
 }
 
-MHD_Result RequestContext::fill_argument(void *__this, enum MHD_ValueKind kind,
+void RequestContext::add_argument(const char *key, const char* value)
-                                         const char *key, const char* value)
 {
-  RequestContext *_this = static_cast<RequestContext*>(__this);
+  RequestContext *_this = this;
   _this->arguments[key].push_back(value == nullptr ? "" : value);
   if ( ! _this->queryString.empty() ) {
     _this->queryString += "&";
@@ -104,15 +105,6 @@ MHD_Result RequestContext::fill_argument(void *__this, enum MHD_ValueKind kind,
     _this->queryString += "=";
     _this->queryString += urlEncode(value);
   }
-  return MHD_YES;
-}
-
-MHD_Result RequestContext::fill_cookie(void *__this, enum MHD_ValueKind kind,
-                                         const char *key, const char* value)
-{
-  RequestContext *_this = static_cast<RequestContext*>(__this);
-  _this->cookies[key] = value == nullptr ? "" : value;
-  return MHD_YES;
 }
 
 void RequestContext::print_debug_info() const {

src/server/request_context.h

@@ -29,7 +29,7 @@
 #include <stdexcept>
 
 #include "byte_range.h"
-#include "tools/stringTools.h"
+#include "../tools/stringTools.h"
 
 extern "C" {
 #include "microhttpd_wrapper.h"
@@ -55,12 +55,17 @@ class IndexError: public std::runtime_error {};
 
 
 class RequestContext {
+  public: // types
+    typedef std::vector<std::pair<const char*, const char*>> NameValuePairs;
+
   public: // functions
-    RequestContext(struct MHD_Connection* connection,
+    RequestContext(const std::string& rootLocation, // URI-encoded
-                   const std::string& rootLocation, // URI-encoded
                    const std::string& unrootedUrl,  // URI-decoded
                    const std::string& method,
-                   const std::string& version);
+                   const std::string& version,
+                   const NameValuePairs& headers,
+                   const NameValuePairs& queryArgs);
+
     ~RequestContext();
 
     void print_debug_info() const;
@@ -145,16 +150,14 @@ class RequestContext {
     ByteRange byteRange_;
     std::map<std::string, std::string> headers;
     std::map<std::string, std::vector<std::string>> arguments;
-    std::map<std::string, std::string> cookies;
     std::string queryString;
     UserLanguage userlang;
 
   private: // functions
     UserLanguage determine_user_language() const;
 
-    static MHD_Result fill_header(void *, enum MHD_ValueKind, const char*, const char*);
+    void add_header(const char* name, const char* value);
-    static MHD_Result fill_cookie(void *, enum MHD_ValueKind, const char*, const char*);
+    void add_argument(const char* name, const char* value);
-    static MHD_Result fill_argument(void *, enum MHD_ValueKind, const char*, const char*);
 };
 
 template<> std::string RequestContext::get_argument(const std::string& name) const;

src/server/response.cpp

@@ -32,6 +32,9 @@
 #include <zlib.h>
 
 #include <array>
+#include <list>
+#include <map>
+#include <regex>
 
 // This is somehow a magic value.
 // If this value is too small, we will compress (and lost cpu time) too much
@@ -47,6 +50,8 @@ namespace kiwix {
 
 namespace
 {
+typedef kainjow::mustache::data MustacheData;
+
 // some utilities
 
 std::string get_mime_type(const zim::Item& item)
@@ -151,14 +156,214 @@ std::unique_ptr<Response> Response::build_304(const ETag& etag)
   return response;
 }
 
-std::string ContentResponseBlueprint::getMessage(const std::string& msgId) const
+
+namespace
 {
-  return getTranslatedString(m_request.get_user_language(), msgId);
+
+// This class was introduced in order to work around the missing support
+// for std::variant (and std::optional) under some of the current build
+// platforms.
+template<class T>
+class Optional
+{
+public: // functions
+    Optional() {}
+    Optional(const T& t) : ptr(new T(t)) {}
+    Optional(const Optional& o) : ptr(o.has_value() ? new T(*o) : nullptr) {}
+    Optional(Optional&& o) : ptr(std::move(o.ptr)) {}
+
+    Optional& operator=(const Optional& o)
+    {
+      *this = Optional(o);
+      return *this;
     }
 
+    Optional& operator=(Optional&& o)
+    {
+      ptr = std::move(o.ptr);
+      return *this;
+    }
+
+    bool has_value() const { return ptr.get() != nullptr; }
+    const T& operator*() const { return *ptr; }
+    T& operator*() { return *ptr; }
+
+private: // data
+    std::unique_ptr<T> ptr;
+};
+
+} // unnamed namespace
+
+class ContentResponseBlueprint::Data
+{
+public:
+  typedef std::list<Data>             List;
+  typedef std::map<std::string, Data> Object;
+
+private:
+  // std::variant<std::string, bool, List, Object> data;
+  // XXX: libkiwix is compiled on platforms where std::variant
+  // XXX: is not yet supported. Hence this hack. Only one
+  // XXX: of the below data members is expected to contain a value.
+  Optional<std::string> m_stringValue;
+  Optional<bool>        m_boolValue;
+  Optional<List>        m_listValue;
+  Optional<Object>      m_objectValue;
+
+public:
+  Data() {}
+  Data(const std::string& s) : m_stringValue(s) {}
+  Data(bool b)               : m_boolValue(b)   {}
+  Data(const List& l)        : m_listValue(l)   {}
+  Data(const Object& o)      : m_objectValue(o) {}
+
+  MustacheData toMustache(const std::string& lang) const;
+
+  Data& operator[](const std::string& key)
+  {
+    return (*m_objectValue)[key];
+  }
+
+  void push_back(const Data& d) { (*m_listValue).push_back(d); }
+
+  static Data onlyAsNonEmptyValue(const std::string& s)
+  {
+    return s.empty() ? Data(false) : Data(s);
+  }
+
+  static Data from(const ParameterizedMessage& pmsg)
+  {
+    Object obj;
+    for(const auto& kv : pmsg.getParams()) {
+      obj[kv.first] = kv.second;
+    }
+    return Object{
+              { "msgid", pmsg.getMsgId() },
+              { "params", Data(obj) }
+    };
+  }
+
+  std::string asJSON() const;
+  void dumpJSON(std::ostream& os) const;
+
+private:
+  bool isString() const { return m_stringValue.has_value(); }
+  bool isList()   const { return m_listValue.has_value();   }
+  bool isObject() const { return m_objectValue.has_value(); }
+
+  const std::string& stringValue() const { return *m_stringValue; }
+  bool               boolValue()   const { return *m_boolValue;   }
+  const List&        listValue()   const { return *m_listValue;   }
+  const Object&      objectValue() const { return *m_objectValue; }
+
+  const Data* get(const std::string& key) const
+  {
+    if ( !isObject() )
+      return nullptr;
+
+    const auto& obj = objectValue();
+    const auto it = obj.find(key);
+    return it != obj.end() ? &it->second : nullptr;
+  }
+};
+
+MustacheData ContentResponseBlueprint::Data::toMustache(const std::string& lang) const
+{
+  if ( this->isList() ) {
+    kainjow::mustache::list l;
+    for ( const auto& x : this->listValue() ) {
+      l.push_back(x.toMustache(lang));
+    }
+    return l;
+  } else if ( this->isObject() ) {
+    const Data* msgId = this->get("msgid");
+    const Data* msgParams = this->get("params");
+    if ( msgId && msgId->isString() && msgParams && msgParams->isObject() ) {
+      std::map<std::string, std::string> params;
+      for(const auto& kv : msgParams->objectValue()) {
+        params[kv.first] = kv.second.stringValue();
+      }
+      const ParameterizedMessage msg(msgId->stringValue(), ParameterizedMessage::Parameters(params));
+      return msg.getText(lang);
+    } else {
+      kainjow::mustache::object o;
+      for ( const auto& kv : this->objectValue() ) {
+        o[kv.first] = kv.second.toMustache(lang);
+      }
+      return o;
+    }
+  } else if ( this->isString() ) {
+    return this->stringValue();
+  } else {
+    return this->boolValue();
+  }
+}
+
+void ContentResponseBlueprint::Data::dumpJSON(std::ostream& os) const
+{
+  if ( this->isString() ) {
+    os << '"' << escapeForJSON(this->stringValue()) << '"';
+  } else if ( this->isList() ) {
+    const char * sep = " ";
+    os << "[";
+
+    for ( const auto& x :  this->listValue() ) {
+      os << sep;
+      x.dumpJSON(os);
+      sep = ", ";
+    }
+    os << " ]";
+  } else if ( this->isObject() ) {
+    const char * sep = " ";
+    os << "{";
+    for ( const auto& kv : this->objectValue() ) {
+      os << sep << '"' << kv.first << "\" : ";
+      kv.second.dumpJSON(os);
+      sep = ", ";
+    }
+    os << " }";
+  } else {
+    os << (this->boolValue() ? "true" : "false");
+  }
+}
+
+std::string ContentResponseBlueprint::Data::asJSON() const
+{
+  std::ostringstream oss;
+  this->dumpJSON(oss);
+
+  // This JSON is going to be used in HTML inside a <script></script> tag.
+  // If it contains "</script>" (or "</script >") as a substring, then the HTML
+  // parser will be confused. Since for a valid JSON that may happen only inside
+  // a JSON string, we can safely take advantage of the answers to
+  // https://stackoverflow.com/questions/28259389/how-to-put-script-in-a-javascript-string
+  // and work around the issue by inserting an otherwise harmless backslash.
+  return std::regex_replace(oss.str(), std::regex("</script"), "</scr\\ipt");
+}
+
+ContentResponseBlueprint::ContentResponseBlueprint(const RequestContext* request,
+                         int httpStatusCode,
+                         const std::string& mimeType,
+                         const std::string& templateStr,
+                         bool includeKiwixResponseData)
+  : m_request(*request)
+  , m_httpStatusCode(httpStatusCode)
+  , m_mimeType(mimeType)
+  , m_template(templateStr)
+  , m_includeKiwixResponseData(includeKiwixResponseData)
+  , m_data(new Data)
+{}
+
+ContentResponseBlueprint::~ContentResponseBlueprint() = default;
+
 std::unique_ptr<ContentResponse> ContentResponseBlueprint::generateResponseObject() const
 {
-  auto r = ContentResponse::build(m_template, m_data, m_mimeType);
+  kainjow::mustache::data d = m_data->toMustache(m_request.get_user_language());
+  if ( m_includeKiwixResponseData ) {
+    d.set("KIWIX_RESPONSE_TEMPLATE", escapeForJSON(m_template, false));
+    d.set("KIWIX_RESPONSE_DATA", m_data->asJSON());
+  }
+  auto r = ContentResponse::build(m_template, d, m_mimeType);
   r->set_code(m_httpStatusCode);
   return r;
 }
@@ -167,26 +372,30 @@ HTTPErrorResponse::HTTPErrorResponse(const RequestContext& request,
                                      int httpStatusCode,
                                      const std::string& pageTitleMsgId,
                                      const std::string& headingMsgId,
-                                     const std::string& cssUrl)
+                                     const std::string& cssUrl,
+                                     bool includeKiwixResponseData)
   : ContentResponseBlueprint(&request,
                              httpStatusCode,
                              request.get_requested_format() == "html" ? "text/html; charset=utf-8" : "application/xml; charset=utf-8",
-                             request.get_requested_format() == "html" ? RESOURCE::templates::error_html : RESOURCE::templates::error_xml)
+                             request.get_requested_format() == "html" ? RESOURCE::templates::error_html : RESOURCE::templates::error_xml,
+                             includeKiwixResponseData)
 {
-  kainjow::mustache::list emptyList;
+  Data::List emptyList;
-  this->m_data = kainjow::mustache::object{
+  *this->m_data = Data(Data::Object{
-                    {"CSS_URL", onlyAsNonEmptyMustacheValue(cssUrl) },
+                    {"CSS_URL", Data::onlyAsNonEmptyValue(cssUrl) },
-                    {"PAGE_TITLE",   getMessage(pageTitleMsgId)},
+                    {"PAGE_TITLE",   Data::from(nonParameterizedMessage(pageTitleMsgId))},
-                    {"PAGE_HEADING", getMessage(headingMsgId)},
+                    {"PAGE_HEADING", Data::from(nonParameterizedMessage(headingMsgId))},
                     {"details", emptyList}
-  };
+  });
 }
 
 HTTP404Response::HTTP404Response(const RequestContext& request)
   : HTTPErrorResponse(request,
                       MHD_HTTP_NOT_FOUND,
                       "404-page-title",
-                      "404-page-heading")
+                      "404-page-heading",
+                      std::string(),
+                      /*includeKiwixResponseData=*/true)
 {
 }
 
@@ -199,8 +408,7 @@ UrlNotFoundResponse::UrlNotFoundResponse(const RequestContext& request)
 
 HTTPErrorResponse& HTTPErrorResponse::operator+(const ParameterizedMessage& details)
 {
-  const std::string msg = details.getText(m_request.get_user_language());
+  (*m_data)["details"].push_back(Data::Object{{"p", Data::from(details)}});
-  m_data["details"].push_back({"p", msg});
   return *this;
 }
 
@@ -215,7 +423,9 @@ HTTP400Response::HTTP400Response(const RequestContext& request)
   : HTTPErrorResponse(request,
                       MHD_HTTP_BAD_REQUEST,
                       "400-page-title",
-                      "400-page-heading")
+                      "400-page-heading",
+                      std::string(),
+                      /*includeKiwixResponseData=*/true)
 {
   std::string requestUrl = urlDecode(m_request.get_full_url(), false);
   const auto query = m_request.get_query();
@@ -229,19 +439,13 @@ HTTP500Response::HTTP500Response(const RequestContext& request)
   : HTTPErrorResponse(request,
                       MHD_HTTP_INTERNAL_SERVER_ERROR,
                       "500-page-title",
-                      "500-page-heading")
+                      "500-page-heading",
+                      std::string(),
+                      /*includeKiwixResponseData=*/true)
 {
   *this += nonParameterizedMessage("500-page-text");
 }
 
-std::unique_ptr<ContentResponse> HTTP500Response::generateResponseObject() const
-{
-  const std::string mimeType = "text/html;charset=utf-8";
-  auto r = ContentResponse::build(m_template, m_data, mimeType);
-  r->set_code(m_httpStatusCode);
-  return r;
-}
-
 std::unique_ptr<Response> Response::build_416(size_t resourceLength)
 {
   auto response = Response::build();

src/server/response.h

@@ -101,6 +101,9 @@ class ContentResponse : public Response {
       kainjow::mustache::data data,
       const std::string& mimetype);
 
+    const std::string& getContent() const { return m_content; }
+    const std::string& getMimeType() const { return m_mimeType; }
+
   private:
     MHD_Response* create_mhd_response(const RequestContext& request);
 
@@ -118,31 +121,28 @@ public: // functions
   ContentResponseBlueprint(const RequestContext* request,
                            int httpStatusCode,
                            const std::string& mimeType,
-                           const std::string& templateStr)
+                           const std::string& templateStr,
-    : m_request(*request)
+                           bool includeKiwixResponseData = false);
-    , m_httpStatusCode(httpStatusCode)
-    , m_mimeType(mimeType)
-    , m_template(templateStr)
-  {}
 
-  virtual ~ContentResponseBlueprint() = default;
+  ~ContentResponseBlueprint();
 
   operator std::unique_ptr<Response>() const
   {
     return generateResponseObject();
   }
 
+  std::unique_ptr<ContentResponse> generateResponseObject() const;
 
-protected: // functions
+protected: // types
-  std::string getMessage(const std::string& msgId) const;
+  class Data;
-  virtual std::unique_ptr<ContentResponse> generateResponseObject() const;
 
-public: //data
+protected: //data
   const RequestContext& m_request;
   const int m_httpStatusCode;
   const std::string m_mimeType;
   const std::string m_template;
-  kainjow::mustache::data m_data;
+  const bool m_includeKiwixResponseData;
+  std::unique_ptr<Data> m_data;
 };
 
 struct HTTPErrorResponse : ContentResponseBlueprint
@@ -151,7 +151,8 @@ struct HTTPErrorResponse : ContentResponseBlueprint
                     int httpStatusCode,
                     const std::string& pageTitleMsgId,
                     const std::string& headingMsgId,
-                    const std::string& cssUrl = "");
+                    const std::string& cssUrl = "",
+                    bool includeKiwixResponseData = false);
 
   HTTPErrorResponse& operator+(const ParameterizedMessage& errorDetails);
   HTTPErrorResponse& operator+=(const ParameterizedMessage& errorDetails);
@@ -175,11 +176,6 @@ struct HTTP400Response : HTTPErrorResponse
 struct HTTP500Response : HTTPErrorResponse
 {
   explicit HTTP500Response(const RequestContext& request);
-
-private: // overrides
-  // generateResponseObject() is overriden in order to produce a minimal
-  // response without any need for additional resources from the server
-  std::unique_ptr<ContentResponse> generateResponseObject() const override;
 };
 
 class ItemResponse : public Response {

src/tools/otherTools.cpp

@@ -327,17 +327,27 @@ std::string kiwix::render_template(const std::string& template_str, kainjow::mus
   return ss.str();
 }
 
-namespace
+// The escapeQuote parameter of escapeForJSON() defaults to true.
-{
+// This constant makes the calls to escapeForJSON() where the quote symbol
+// should not be escaped (as it is later replaced with the HTML character entity
+// ") more readable.
+static const bool DONT_ESCAPE_QUOTE = false;
 
-std::string escapeForJSON(const std::string& s)
+std::string kiwix::escapeForJSON(const std::string& s, bool escapeQuote)
 {
   std::ostringstream oss;
   for (char c : s) {
     if ( c == '\\' ) {
       oss << "\\\\";
     } else if ( unsigned(c) < 0x20U ) {
-      oss << "\\u" << std::setw(4) << std::setfill('0') << unsigned(c);
+      switch ( c ) {
+      case '\n': oss << "\\n"; break;
+      case '\r': oss << "\\r"; break;
+      case '\t': oss << "\\t"; break;
+      default:   oss << "\\u" << std::setw(4) << std::setfill('0') << unsigned(c);
+      }
+    } else if ( c == '"' && escapeQuote ) {
+      oss << "\\\"";
     } else {
       oss << c;
     }
@@ -345,6 +355,9 @@ std::string escapeForJSON(const std::string& s)
   return oss.str();
 }
 
+namespace
+{
+
 std::string makeFulltextSearchSuggestion(const std::string& lang,
                                          const std::string& queryString)
 {
@@ -370,10 +383,10 @@ void kiwix::Suggestions::add(const zim::SuggestionItem& suggestion)
                           ? suggestion.getSnippet()
                           : suggestion.getTitle();
 
-  result.set("label", escapeForJSON(label));
+  result.set("label", escapeForJSON(label, DONT_ESCAPE_QUOTE));
-  result.set("value", escapeForJSON(suggestion.getTitle()));
+  result.set("value", escapeForJSON(suggestion.getTitle(), DONT_ESCAPE_QUOTE));
   result.set("kind", "path");
-  result.set("path", escapeForJSON(suggestion.getPath()));
+  result.set("path", escapeForJSON(suggestion.getPath(), DONT_ESCAPE_QUOTE));
   result.set("first", m_data.is_empty_list());
   m_data.push_back(result);
 }
@@ -383,8 +396,8 @@ void kiwix::Suggestions::addFTSearchSuggestion(const std::string& uiLang,
 {
   kainjow::mustache::data result;
   const std::string label = makeFulltextSearchSuggestion(uiLang, queryString);
-  result.set("label", escapeForJSON(label));
+  result.set("label", escapeForJSON(label, DONT_ESCAPE_QUOTE));
-  result.set("value", escapeForJSON(queryString + " "));
+  result.set("value", escapeForJSON(queryString + " ", DONT_ESCAPE_QUOTE));
   result.set("kind", "pattern");
   result.set("first", m_data.is_empty_list());
   m_data.push_back(result);

src/tools/stringTools.h

@@ -53,6 +53,7 @@ private:
   const icu::Locale locale;
 };
 
+std::string escapeForJSON(const std::string& s, bool escapeQuote = true);
 
 /* urlEncode() is the equivalent of JS encodeURIComponent(), with the only
  * difference that the slash (/) symbol is NOT encoded. */

static/skin/i18n.js

@@ -69,6 +69,37 @@ function $t(msgId, params={}) {
   }
 }
 
+const I18n = {
+  instantiateParameterizedMessages: function(data) {
+    if ( data.__proto__ == Array.prototype ) {
+      const result = [];
+      for ( const x of data ) {
+        result.push(this.instantiateParameterizedMessages(x));
+      }
+      return result;
+    } else if ( data.__proto__ == Object.prototype ) {
+      const msgId = data.msgid;
+      const msgParams = data.params;
+      if ( msgId && msgId.__proto__ == String.prototype && msgParams && msgParams.__proto__ == Object.prototype ) {
+        return $t(msgId, msgParams);
+      } else {
+        const result = {};
+        for ( const p in data ) {
+          result[p] = this.instantiateParameterizedMessages(data[p]);
+        }
+        return result;
+      }
+    } else {
+      return data;
+    }
+  },
+
+  render: function (template, params) {
+    params = this.instantiateParameterizedMessages(params);
+    return mustache.render(template, params);
+  }
+}
+
 const DEFAULT_UI_LANGUAGE = 'en';
 
 Translations.load(DEFAULT_UI_LANGUAGE, /*asDefault=*/true);
@@ -145,3 +176,4 @@ window.$t = $t;
 window.getUserLanguage = getUserLanguage;
 window.setUserLanguage = setUserLanguage;
 window.initUILanguageSelector = initUILanguageSelector;
+window.I18n = I18n;

static/skin/viewer.js

@@ -249,6 +249,25 @@ function handle_location_hash_change() {
   history.replaceState(viewerState, null);
 }
 
+function translateErrorPageIfNeeded() {
+  const cw = contentIframe.contentWindow;
+  if ( cw.KIWIX_RESPONSE_TEMPLATE && cw.KIWIX_RESPONSE_DATA ) {
+    const template = htmlDecode(cw.KIWIX_RESPONSE_TEMPLATE);
+
+    // cw.KIWIX_RESPONSE_DATA belongs to the iframe context and running
+    // I18n.render() on it directly in the top context doesn't work correctly
+    // because the type checks (obj.__proto__ == ???.prototype) in
+    // I18n.instantiateParameterizedMessages() always fail (String.prototype
+    // refers to different objects in different contexts).
+    // Work arround that issue by copying the object into our context.
+    const params = JSON.parse(JSON.stringify(cw.KIWIX_RESPONSE_DATA));
+
+    const html = I18n.render(template, params);
+    const htmlDoc = new DOMParser().parseFromString(html, "text/html");
+    cw.document.documentElement.innerHTML = htmlDoc.documentElement.innerHTML;
+  }
+}
+
 function handle_content_url_change() {
   const iframeLocation = contentIframe.contentWindow.location;
   console.log('handle_content_url_change: ' + iframeLocation.href);
@@ -258,6 +277,7 @@ function handle_content_url_change() {
   const newHash = iframeUrl2UserUrl(iframeContentUrl, iframeContentQuery);
   history.replaceState(viewerState, null, makeURL(location.search, newHash));
   updateCurrentBookIfNeeded(newHash);
+  translateErrorPageIfNeeded();
 };
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -496,6 +516,7 @@ function changeUILanguage() {
   viewerState.uiLanguage = lang;
   setUserLanguage(lang, () => {
     updateUIText();
+    translateErrorPageIfNeeded();
     history.pushState(viewerState, null);
   });
 }

static/templates/error.html

@@ -5,7 +5,10 @@
     <title>{{PAGE_TITLE}}</title>
 {{#CSS_URL}}
     <link type="text/css" href="{{{CSS_URL}}}" rel="Stylesheet" />
-{{/CSS_URL}}
+{{/CSS_URL}}{{#KIWIX_RESPONSE_DATA}}    <script>
+      window.KIWIX_RESPONSE_TEMPLATE = "{{KIWIX_RESPONSE_TEMPLATE}}";
+      window.KIWIX_RESPONSE_DATA = {{{KIWIX_RESPONSE_DATA}}};
+    </script>{{/KIWIX_RESPONSE_DATA}}
   </head>
   <body>
     <h1>{{PAGE_HEADING}}</h1>

test/i18n.cpp

@@ -0,0 +1,50 @@
+#include "../src/server/i18n.h"
+#include "gtest/gtest.h"
+
+using namespace kiwix;
+
+TEST(ParameterizedMessage, parameterlessMessages)
+{
+  {
+    const ParameterizedMessage msg("404-page-title", {});
+
+    EXPECT_EQ(msg.getText("en"),   "Content not found");
+    EXPECT_EQ(msg.getText("test"), "[I18N TESTING] Not Found - Try Again");
+  }
+
+  {
+    // Make sure that msgId influences the result of getText()
+    const ParameterizedMessage msg("random-page-button-text", {});
+
+    EXPECT_EQ(msg.getText("en"),   "Go to a randomly selected page");
+    EXPECT_EQ(msg.getText("test"), "[I18N TESTING] I am tired of determinism");
+  }
+
+  {
+    // Demonstrate that unwanted parameters are silently ignored
+    const ParameterizedMessage msg("404-page-title", {{"abc", "xyz"}});
+
+    EXPECT_EQ(msg.getText("en"),   "Content not found");
+    EXPECT_EQ(msg.getText("test"), "[I18N TESTING] Not Found - Try Again");
+  }
+}
+
+TEST(ParameterizedMessage, messagesWithParameters)
+{
+  {
+    const ParameterizedMessage msg("filter-by-tag",
+                                   {{"TAG", "scifi"}}
+    );
+
+    EXPECT_EQ(msg.getText("en"),   "Filter by tag \"scifi\"");
+    EXPECT_EQ(msg.getText("test"), "Filter [I18N] by [TESTING] tag \"scifi\"");
+  }
+
+  {
+    // Omitting expected parameters amounts to using empty values for them
+    const ParameterizedMessage msg("filter-by-tag", {});
+
+    EXPECT_EQ(msg.getText("en"),   "Filter by tag \"\"");
+    EXPECT_EQ(msg.getText("test"), "Filter [I18N] by [TESTING] tag \"\"");
+  }
+}

test/meson.build

@@ -13,7 +13,9 @@ tests = [
     'name_mapper',
     'opds_catalog',
     'server_helper',
-    'lrucache'
+    'lrucache',
+    'i18n',
+    'response'
 ]
 
 if build_machine.system() != 'windows'

test/otherTools.cpp

@@ -110,10 +110,10 @@ TEST(Suggestions, specialCharHandling)
     CHECK_SUGGESTIONS(s.getJSON(),
 R"EXPECTEDJSON([
   {
-    "value" : "Title with \u0009\u0010\u0013\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?",
+    "value" : "Title with \t\n\r\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?",
-    "label" : "Snippet with \u0009\u0010\u0013\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?",
+    "label" : "Snippet with \t\n\r\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?",
     "kind" : "path"
-      , "path" : "Path with \u0009\u0010\u0013\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?"
+      , "path" : "Path with \t\n\r\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?"
   }
 ]
 )EXPECTEDJSON"
@@ -128,10 +128,10 @@ R"EXPECTEDJSON([
     CHECK_SUGGESTIONS(s.getJSON(),
 R"EXPECTEDJSON([
   {
-    "value" : "Snippetless title with \u0009\u0010\u0013\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?",
+    "value" : "Snippetless title with \t\n\r\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?",
-    "label" : "Snippetless title with \u0009\u0010\u0013\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?",
+    "label" : "Snippetless title with \t\n\r\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?",
     "kind" : "path"
-      , "path" : "Path with \u0009\u0010\u0013\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?"
+      , "path" : "Path with \t\n\r\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?"
   }
 ]
 )EXPECTEDJSON"
@@ -145,8 +145,8 @@ R"EXPECTEDJSON([
     CHECK_SUGGESTIONS(s.getJSON(),
 R"EXPECTEDJSON([
   {
-    "value" : "text with \u0009\u0010\u0013\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.? ",
+    "value" : "text with \t\n\r\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.? ",
-    "label" : "containing 'text with \u0009\u0010\u0013\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?'...",
+    "label" : "containing 'text with \t\n\r\\<>&'"~!@#$%^*()_+`-=[]{}|:;,.?'...",
     "kind" : "pattern"
     //EOLWHITESPACEMARKER
   }

test/response.cpp

@@ -0,0 +1,101 @@
+#include "../src/server/response.h"
+#include "gtest/gtest.h"
+
+#include "../src/server/request_context.h"
+
+namespace
+{
+
+using namespace kiwix;
+
+RequestContext makeHttpGetRequest(const std::string& url,
+                                  const RequestContext::NameValuePairs& headers,
+                                  const RequestContext::NameValuePairs& queryArgs)
+{
+  return RequestContext("", url, "GET", "1.1", headers, queryArgs);
+}
+
+std::string getResponseContent(const ContentResponseBlueprint& crb)
+{
+  return crb.generateResponseObject()->getContent();
+}
+
+} // unnamed namespace
+
+
+
+TEST(HTTPErrorResponse, shouldBeInEnglishByDefault) {
+  const RequestContext req = makeHttpGetRequest("/asdf", {}, {});
+  HTTPErrorResponse errResp(req, MHD_HTTP_NOT_FOUND,
+                            "404-page-title",
+                            "404-page-heading",
+                            "/css/error.css",
+                            /*includeKiwixResponseData=*/true);
+
+  errResp += ParameterizedMessage("suggest-search",
+                              {
+                                { "PATTERN",    "asdf"   },
+                                { "SEARCH_URL", "/search?q=asdf" }
+             });
+
+  EXPECT_EQ(getResponseContent(errResp),
+R"(<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <meta content="text/html;charset=UTF-8" http-equiv="content-type" />
+    <title>Content not found</title>
+    <link type="text/css" href="/css/error.css" rel="Stylesheet" />
+    <script>
+      window.KIWIX_RESPONSE_TEMPLATE = "&lt;!DOCTYPE html&gt;\n&lt;html xmlns=&quot;http://www.w3.org/1999/xhtml&quot;&gt;\n  &lt;head&gt;\n    &lt;meta content=&quot;text/html;charset=UTF-8&quot; http-equiv=&quot;content-type&quot; /&gt;\n    &lt;title&gt;{{PAGE_TITLE}}&lt;/title&gt;\n{{#CSS_URL}}\n    &lt;link type=&quot;text/css&quot; href=&quot;{{{CSS_URL}}}&quot; rel=&quot;Stylesheet&quot; /&gt;\n{{/CSS_URL}}{{#KIWIX_RESPONSE_DATA}}    &lt;script&gt;\n      window.KIWIX_RESPONSE_TEMPLATE = &quot;{{KIWIX_RESPONSE_TEMPLATE}}&quot;;\n      window.KIWIX_RESPONSE_DATA = {{{KIWIX_RESPONSE_DATA}}};\n    &lt;/script&gt;{{/KIWIX_RESPONSE_DATA}}\n  &lt;/head&gt;\n  &lt;body&gt;\n    &lt;h1&gt;{{PAGE_HEADING}}&lt;/h1&gt;\n{{#details}}\n    &lt;p&gt;\n      {{{p}}}\n    &lt;/p&gt;\n{{/details}}\n  &lt;/body&gt;\n&lt;/html&gt;\n";
+      window.KIWIX_RESPONSE_DATA = { "CSS_URL" : "/css/error.css", "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "suggest-search", "params" : { "PATTERN" : "asdf", "SEARCH_URL" : "/search?q=asdf" } } } ] };
+    </script>
+  </head>
+  <body>
+    <h1>Not Found</h1>
+    <p>
+      Make a full text search for <a href="/search?q=asdf">asdf</a>
+    </p>
+  </body>
+</html>
+)");
+}
+
+TEST(HTTPErrorResponse, shouldBeTranslatable) {
+  const RequestContext req = makeHttpGetRequest("/asdf",
+                              /* headers */     {},
+                              /* query args */  {{"userlang", "test"}}
+  );
+
+  HTTPErrorResponse errResp(req, MHD_HTTP_NOT_FOUND,
+                            "404-page-title",
+                            "404-page-heading",
+                            "/css/error.css",
+                            /*includeKiwixResponseData=*/true);
+
+  errResp += ParameterizedMessage("suggest-search",
+                              {
+                                { "PATTERN",    "asdf"   },
+                                { "SEARCH_URL", "/search?q=asdf" }
+             });
+
+  EXPECT_EQ(getResponseContent(errResp),
+R"(<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <meta content="text/html;charset=UTF-8" http-equiv="content-type" />
+    <title>[I18N TESTING] Not Found - Try Again</title>
+    <link type="text/css" href="/css/error.css" rel="Stylesheet" />
+    <script>
+      window.KIWIX_RESPONSE_TEMPLATE = "&lt;!DOCTYPE html&gt;\n&lt;html xmlns=&quot;http://www.w3.org/1999/xhtml&quot;&gt;\n  &lt;head&gt;\n    &lt;meta content=&quot;text/html;charset=UTF-8&quot; http-equiv=&quot;content-type&quot; /&gt;\n    &lt;title&gt;{{PAGE_TITLE}}&lt;/title&gt;\n{{#CSS_URL}}\n    &lt;link type=&quot;text/css&quot; href=&quot;{{{CSS_URL}}}&quot; rel=&quot;Stylesheet&quot; /&gt;\n{{/CSS_URL}}{{#KIWIX_RESPONSE_DATA}}    &lt;script&gt;\n      window.KIWIX_RESPONSE_TEMPLATE = &quot;{{KIWIX_RESPONSE_TEMPLATE}}&quot;;\n      window.KIWIX_RESPONSE_DATA = {{{KIWIX_RESPONSE_DATA}}};\n    &lt;/script&gt;{{/KIWIX_RESPONSE_DATA}}\n  &lt;/head&gt;\n  &lt;body&gt;\n    &lt;h1&gt;{{PAGE_HEADING}}&lt;/h1&gt;\n{{#details}}\n    &lt;p&gt;\n      {{{p}}}\n    &lt;/p&gt;\n{{/details}}\n  &lt;/body&gt;\n&lt;/html&gt;\n";
+      window.KIWIX_RESPONSE_DATA = { "CSS_URL" : "/css/error.css", "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "suggest-search", "params" : { "PATTERN" : "asdf", "SEARCH_URL" : "/search?q=asdf" } } } ] };
+    </script>
+  </head>
+  <body>
+    <h1>[I18N TESTING] Content not found, but at least the server is alive</h1>
+    <p>
+      [I18N TESTING] Make a full text search for <a href="/search?q=asdf">asdf</a>
+    </p>
+  </body>
+</html>
+)");
+}

test/server.cpp

@@ -59,7 +59,7 @@ const ResourceCollection resources200Compressible{
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/autoComplete/css/autoComplete.css" },
   { STATIC_CONTENT,  "/ROOT%23%3F/skin/autoComplete/css/autoComplete.css?cacheid=ef30cd42" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/i18n.js" },
-  { STATIC_CONTENT,  "/ROOT%23%3F/skin/i18n.js?cacheid=6a8c6fb2" },
+  { STATIC_CONTENT,  "/ROOT%23%3F/skin/i18n.js?cacheid=4ab55b42" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/index.css" },
   { STATIC_CONTENT,  "/ROOT%23%3F/skin/index.css?cacheid=1e78e7cf" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/index.js" },
@@ -75,7 +75,7 @@ const ResourceCollection resources200Compressible{
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/taskbar.css" },
   { STATIC_CONTENT,  "/ROOT%23%3F/skin/taskbar.css?cacheid=e014a885" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/viewer.js" },
-  { STATIC_CONTENT,  "/ROOT%23%3F/skin/viewer.js?cacheid=948df083" },
+  { STATIC_CONTENT,  "/ROOT%23%3F/skin/viewer.js?cacheid=e9c025f2" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/fonts/Poppins.ttf" },
   { STATIC_CONTENT,  "/ROOT%23%3F/skin/fonts/Poppins.ttf?cacheid=af705837" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/fonts/Roboto.ttf" },
@@ -285,7 +285,7 @@ R"EXPECTEDRESULT(      href="/ROOT%23%3F/skin/kiwix.css?cacheid=2158fad9"
     <link rel="mask-icon" href="/ROOT%23%3F/skin/favicon/safari-pinned-tab.svg?cacheid=8d487e95" color="#5bbad5">
     <link rel="shortcut icon" href="/ROOT%23%3F/skin/favicon/favicon.ico?cacheid=92663314">
     <meta name="msapplication-config" content="/ROOT%23%3F/skin/favicon/browserconfig.xml?cacheid=f29a7c4a">
-    <script type="module" src="/ROOT%23%3F/skin/i18n.js?cacheid=6a8c6fb2" defer></script>
+    <script type="module" src="/ROOT%23%3F/skin/i18n.js?cacheid=4ab55b42" defer></script>
     <script type="text/javascript" src="/ROOT%23%3F/skin/languages.js?cacheid=96f2cf73" defer></script>
     <script src="/ROOT%23%3F/skin/isotope.pkgd.min.js?cacheid=2e48d392" defer></script>
     <script src="/ROOT%23%3F/skin/iso6391To3.js?cacheid=ecde2bb3"></script>
@@ -318,9 +318,9 @@ R"EXPECTEDRESULT(                                <img src="${root}/skin/download
 R"EXPECTEDRESULT(    <link type="text/css" href="./skin/kiwix.css?cacheid=2158fad9" rel="Stylesheet" />
     <link type="text/css" href="./skin/taskbar.css?cacheid=e014a885" rel="Stylesheet" />
     <link type="text/css" href="./skin/autoComplete/css/autoComplete.css?cacheid=ef30cd42" rel="Stylesheet" />
-    <script type="module" src="./skin/i18n.js?cacheid=6a8c6fb2" defer></script>
+    <script type="module" src="./skin/i18n.js?cacheid=4ab55b42" defer></script>
     <script type="text/javascript" src="./skin/languages.js?cacheid=96f2cf73" defer></script>
-    <script type="text/javascript" src="./skin/viewer.js?cacheid=948df083" defer></script>
+    <script type="text/javascript" src="./skin/viewer.js?cacheid=e9c025f2" defer></script>
     <script type="text/javascript" src="./skin/autoComplete/autoComplete.min.js?cacheid=1191aaaf"></script>
       const blankPageUrl = root + "/skin/blank.html?cacheid=6b1fa032";
           <label for="kiwix_button_show_toggle"><img src="./skin/caret.png?cacheid=22b942b4" alt=""></label>
@@ -337,6 +337,7 @@ R"EXPECTEDRESULT(    <link type="text/css" href="./skin/kiwix.css?cacheid=2158fa
       // a page rendered from static/templates/no_search_result_html
       /* url */ "/ROOT%23%3F/search?content=poor&pattern=whatever",
 R"EXPECTEDRESULT(    <link type="text/css" href="/ROOT%23%3F/skin/search_results.css?cacheid=76d39c84" rel="Stylesheet" />
+      window.KIWIX_RESPONSE_DATA = { "CSS_URL" : "/ROOT%23%3F/skin/search_results.css?cacheid=76d39c84", "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "fulltext-search-unavailable", "params" : { } }, "details" : [ { "p" : { "msgid" : "no-search-results", "params" : { } } } ] };
 )EXPECTEDRESULT"
     },
   };
@@ -535,6 +536,7 @@ struct ExpectedResponseData
 {
   const std::string expectedPageTitle;
   const std::string expectedCssUrl;
+  const std::string expectedKiwixResponseData;
   const std::string bookName;
   const std::string bookTitle;
   const std::string expectedBody;
@@ -544,6 +546,7 @@ enum ExpectedResponseDataType
 {
   expected_page_title,
   expected_css_url,
+  expected_kiwix_response_data,
   book_name,
   book_title,
   expected_body
@@ -556,11 +559,13 @@ ExpectedResponseData operator==(ExpectedResponseDataType t, std::string s)
 {
   switch (t)
   {
-    case expected_page_title: return ExpectedResponseData{s, "", "", "", ""};
+    case expected_page_title: return ExpectedResponseData{s, "", "", "", "", ""};
-    case expected_css_url:    return ExpectedResponseData{"", s, "", "", ""};
+    case expected_css_url:    return ExpectedResponseData{"", s, "", "", "", ""};
-    case book_name:           return ExpectedResponseData{"", "", s, "", ""};
+    case expected_kiwix_response_data:
-    case book_title:          return ExpectedResponseData{"", "", "", s, ""};
+                              return ExpectedResponseData{"", "", s, "", "", ""};
-    case expected_body:       return ExpectedResponseData{"", "", "", "", s};
+    case book_name:           return ExpectedResponseData{"", "", "", s, "", ""};
+    case book_title:          return ExpectedResponseData{"", "", "", "", s, ""};
+    case expected_body:       return ExpectedResponseData{"", "", "", "", "", s};
     default: assert(false); return ExpectedResponseData{};
   }
 }
@@ -579,6 +584,7 @@ ExpectedResponseData operator&&(const ExpectedResponseData& a,
   return ExpectedResponseData{
     selectNonEmpty(a.expectedPageTitle, b.expectedPageTitle),
     selectNonEmpty(a.expectedCssUrl, b.expectedCssUrl),
+    selectNonEmpty(a.expectedKiwixResponseData, b.expectedKiwixResponseData),
     selectNonEmpty(a.bookName, b.bookName),
     selectNonEmpty(a.bookTitle, b.bookTitle),
     selectNonEmpty(a.expectedBody, b.expectedBody)
@@ -607,19 +613,29 @@ private:
 std::string TestContentIn404HtmlResponse::expectedResponse() const
 {
   const std::string frag[] =  {
+    // frag[0]
     R"FRAG(<!DOCTYPE html>
 <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
     <meta content="text/html;charset=UTF-8" http-equiv="content-type" />
     <title>)FRAG",
 
+    // frag[1]
     R"FRAG(</title>
 )FRAG",
 
-    R"FRAG(
+    // frag[2]
+    R"(    <script>
+      window.KIWIX_RESPONSE_TEMPLATE = )" + ERROR_HTML_TEMPLATE_JS_STRING + R"(;
+      window.KIWIX_RESPONSE_DATA = )",
+
+    // frag[3]
+    R"FRAG(;
+    </script>
   </head>
   <body>)FRAG",
 
+  // frag[4]
   R"FRAG(  </body>
 </html>
 )FRAG"
@@ -630,8 +646,10 @@ std::string TestContentIn404HtmlResponse::expectedResponse() const
        + frag[1]
        + pageCssLink()
        + frag[2]
+       + expectedKiwixResponseData
+       + frag[3]
        + expectedBody
-       + frag[3];
+       + frag[4];
 }
 
 std::string TestContentIn404HtmlResponse::pageTitle() const
@@ -648,7 +666,8 @@ std::string TestContentIn404HtmlResponse::pageCssLink() const
 
   return R"(    <link type="text/css" href=")"
        + expectedCssUrl
-       + R"(" rel="Stylesheet" />)";
+       + R"(" rel="Stylesheet" />)"
+       + "\n";
 }
 
 class TestContentIn400HtmlResponse : public TestContentIn404HtmlResponse
@@ -676,6 +695,7 @@ TEST_F(ServerTest, Http404HtmlError)
   using namespace TestingOfHtmlResponses;
   const std::vector<TestContentIn404HtmlResponse> testData{
     { /* url */ "/ROOT%23%3F/random?content=non-existent-book",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "no-such-book", "params" : { "BOOK_NAME" : "non-existent-book" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -685,6 +705,7 @@ TEST_F(ServerTest, Http404HtmlError)
 
     { /* url */ "/ROOT%23%3F/random?content=non-existent-book&userlang=test",
       expected_page_title=="[I18N TESTING] Not Found - Try Again" &&
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "no-such-book", "params" : { "BOOK_NAME" : "non-existent-book" } } } ] })" &&
       expected_body==R"(
     <h1>[I18N TESTING] Content not found, but at least the server is alive</h1>
     <p>
@@ -693,6 +714,7 @@ TEST_F(ServerTest, Http404HtmlError)
 )"  },
 
     { /* url */ "/ROOT%23%3F/suggest?content=no-such-book&term=whatever",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "no-such-book", "params" : { "BOOK_NAME" : "no-such-book" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -701,6 +723,7 @@ TEST_F(ServerTest, Http404HtmlError)
 )"  },
 
     { /* url */ "/ROOT%23%3F/catalog/",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/catalog/" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -710,6 +733,7 @@ TEST_F(ServerTest, Http404HtmlError)
 
     { /* url */ "/ROOT%23%3F/catalog/?userlang=test",
       expected_page_title=="[I18N TESTING] Not Found - Try Again" &&
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/catalog/" } } } ] })" &&
       expected_body==R"(
     <h1>[I18N TESTING] Content not found, but at least the server is alive</h1>
     <p>
@@ -718,6 +742,7 @@ TEST_F(ServerTest, Http404HtmlError)
 )"  },
 
     { /* url */ "/ROOT%23%3F/catalog/invalid_endpoint",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/catalog/invalid_endpoint" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -727,6 +752,7 @@ TEST_F(ServerTest, Http404HtmlError)
 
     { /* url */ "/ROOT%23%3F/catalog/invalid_endpoint?userlang=test",
       expected_page_title=="[I18N TESTING] Not Found - Try Again" &&
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/catalog/invalid_endpoint" } } } ] })" &&
       expected_body==R"(
     <h1>[I18N TESTING] Content not found, but at least the server is alive</h1>
     <p>
@@ -735,6 +761,7 @@ TEST_F(ServerTest, Http404HtmlError)
 )"  },
 
     { /* url */ "/ROOT%23%3F/content/invalid-book/whatever",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/content/invalid-book/whatever" } } }, { "p" : { "msgid" : "suggest-search", "params" : { "PATTERN" : "whatever", "SEARCH_URL" : "/ROOT%23%3F/search?pattern=whatever" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -748,6 +775,7 @@ TEST_F(ServerTest, Http404HtmlError)
     { /* url */ "/ROOT%23%3F/content/zimfile/invalid-article",
       book_name=="zimfile" &&
       book_title=="Ray Charles" &&
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/content/zimfile/invalid-article" } } }, { "p" : { "msgid" : "suggest-search", "params" : { "PATTERN" : "invalid-article", "SEARCH_URL" : "/ROOT%23%3F/search?content=zimfile&pattern=invalid-article" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -759,6 +787,7 @@ TEST_F(ServerTest, Http404HtmlError)
 )"  },
 
     { /* url */ R"(/ROOT%23%3F/content/"><svg onload=alert(1)>)",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/content/\"><svg onload%3Dalert(1)>" } } }, { "p" : { "msgid" : "suggest-search", "params" : { "PATTERN" : "\"><svg onload=alert(1)>", "SEARCH_URL" : "/ROOT%23%3F/search?pattern=%22%3E%3Csvg%20onload%3Dalert(1)%3E" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -772,6 +801,7 @@ TEST_F(ServerTest, Http404HtmlError)
     { /* url */ R"(/ROOT%23%3F/content/zimfile/"><svg onload=alert(1)>)",
       book_name=="zimfile" &&
       book_title=="Ray Charles" &&
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/content/zimfile/\"><svg onload%3Dalert(1)>" } } }, { "p" : { "msgid" : "suggest-search", "params" : { "PATTERN" : "\"><svg onload=alert(1)>", "SEARCH_URL" : "/ROOT%23%3F/search?content=zimfile&pattern=%22%3E%3Csvg%20onload%3Dalert(1)%3E" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -782,10 +812,27 @@ TEST_F(ServerTest, Http404HtmlError)
     </p>
 )"  },
 
+    // XXX: This test case is against a "</script>" string appearing inside
+    // XXX: javascript code that will confuse the HTML parser
+    { /* url */ R"(/ROOT%23%3F/content/zimfile/</script>)",
+      book_name=="zimfile" &&
+      book_title=="Ray Charles" &&
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/content/zimfile/</scr\ipt>" } } }, { "p" : { "msgid" : "suggest-search", "params" : { "PATTERN" : "script>", "SEARCH_URL" : "/ROOT%23%3F/search?content=zimfile&pattern=script%3E" } } } ] })" &&
+      expected_body==R"(
+    <h1>Not Found</h1>
+    <p>
+      The requested URL "/ROOT%23%3F/content/zimfile/&lt;/script&gt;" was not found on this server.
+    </p>
+    <p>
+      Make a full text search for <a href="/ROOT%23%3F/search?content=zimfile&pattern=script%3E">script&gt;</a>
+    </p>
+)"  },
+
     { /* url */ "/ROOT%23%3F/content/zimfile/invalid-article?userlang=test",
       expected_page_title=="[I18N TESTING] Not Found - Try Again" &&
       book_name=="zimfile" &&
       book_title=="Ray Charles" &&
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/content/zimfile/invalid-article" } } }, { "p" : { "msgid" : "suggest-search", "params" : { "PATTERN" : "invalid-article", "SEARCH_URL" : "/ROOT%23%3F/search?content=zimfile&pattern=invalid-article" } } } ] })" &&
       expected_body==R"(
     <h1>[I18N TESTING] Content not found, but at least the server is alive</h1>
     <p>
@@ -797,6 +844,7 @@ TEST_F(ServerTest, Http404HtmlError)
 )"  },
 
     { /* url */ "/ROOT%23%3F/raw/no-such-book/meta/Title",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/raw/no-such-book/meta/Title" } } }, { "p" : { "msgid" : "no-such-book", "params" : { "BOOK_NAME" : "no-such-book" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -808,6 +856,7 @@ TEST_F(ServerTest, Http404HtmlError)
 )"  },
 
     { /* url */ "/ROOT%23%3F/raw/zimfile/XYZ",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/raw/zimfile/XYZ" } } }, { "p" : { "msgid" : "invalid-raw-data-type", "params" : { "DATATYPE" : "XYZ" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -819,6 +868,7 @@ TEST_F(ServerTest, Http404HtmlError)
 )"  },
 
     { /* url */ "/ROOT%23%3F/raw/zimfile/meta/invalid-metadata",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/raw/zimfile/meta/invalid-metadata" } } }, { "p" : { "msgid" : "raw-entry-not-found", "params" : { "DATATYPE" : "meta", "ENTRY" : "invalid-metadata" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -830,6 +880,7 @@ TEST_F(ServerTest, Http404HtmlError)
 )"  },
 
     { /* url */ "/ROOT%23%3F/raw/zimfile/content/invalid-article",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "404-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "url-not-found", "params" : { "url" : "/ROOT%23%3F/raw/zimfile/content/invalid-article" } } }, { "p" : { "msgid" : "raw-entry-not-found", "params" : { "DATATYPE" : "content", "ENTRY" : "invalid-article" } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -845,6 +896,7 @@ TEST_F(ServerTest, Http404HtmlError)
       expected_css_url=="/ROOT%23%3F/skin/search_results.css?cacheid=76d39c84" &&
       book_name=="poor" &&
       book_title=="poor" &&
+      expected_kiwix_response_data==R"({ "CSS_URL" : "/ROOT%23%3F/skin/search_results.css?cacheid=76d39c84", "PAGE_HEADING" : { "msgid" : "404-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "fulltext-search-unavailable", "params" : { } }, "details" : [ { "p" : { "msgid" : "no-search-results", "params" : { } } } ] })" &&
       expected_body==R"(
     <h1>Not Found</h1>
     <p>
@@ -866,6 +918,7 @@ TEST_F(ServerTest, Http400HtmlError)
   using namespace TestingOfHtmlResponses;
   const std::vector<TestContentIn400HtmlResponse> testData{
     { /* url */ "/ROOT%23%3F/search",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "400-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "400-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "invalid-request", "params" : { "url" : "/ROOT%23%3F/search" } } }, { "p" : { "msgid" : "too-many-books", "params" : { "LIMIT" : "3", "NB_BOOKS" : "4" } } } ] })" &&
       expected_body== R"(
     <h1>Invalid request</h1>
     <p>
@@ -876,6 +929,7 @@ TEST_F(ServerTest, Http400HtmlError)
     </p>
 )"  },
     { /* url */ "/ROOT%23%3F/search?content=zimfile",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "400-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "400-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "invalid-request", "params" : { "url" : "/ROOT%23%3F/search?content=zimfile" } } }, { "p" : { "msgid" : "no-query", "params" : { } } } ] })" &&
       expected_body==R"(
     <h1>Invalid request</h1>
     <p>
@@ -886,6 +940,7 @@ TEST_F(ServerTest, Http400HtmlError)
     </p>
 )"  },
     { /* url */ "/ROOT%23%3F/search?content=non-existing-book&pattern=asdfqwerty",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "400-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "400-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "invalid-request", "params" : { "url" : "/ROOT%23%3F/search?content=non-existing-book&pattern=asdfqwerty" } } }, { "p" : { "msgid" : "no-such-book", "params" : { "BOOK_NAME" : "non-existing-book" } } } ] })" &&
       expected_body==R"(
     <h1>Invalid request</h1>
     <p>
@@ -896,6 +951,7 @@ TEST_F(ServerTest, Http400HtmlError)
     </p>
 )"  },
     { /* url */ "/ROOT%23%3F/search?content=non-existing-book&pattern=a\"<script foo>",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "400-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "400-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "invalid-request", "params" : { "url" : "/ROOT%23%3F/search?content=non-existing-book&pattern=a%22%3Cscript%20foo%3E" } } }, { "p" : { "msgid" : "no-such-book", "params" : { "BOOK_NAME" : "non-existing-book" } } } ] })" &&
       expected_body==R"(
     <h1>Invalid request</h1>
     <p>
@@ -908,6 +964,7 @@ TEST_F(ServerTest, Http400HtmlError)
     // There is a flaw in our way to handle query string, we cannot differenciate
     // between `pattern` and `pattern=`
     { /* url */ "/ROOT%23%3F/search?books.filter.lang=eng&pattern",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "400-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "400-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "invalid-request", "params" : { "url" : "/ROOT%23%3F/search?books.filter.lang=eng&pattern" } } }, { "p" : { "msgid" : "no-query", "params" : { } } } ] })" &&
       expected_body==R"(
     <h1>Invalid request</h1>
     <p>
@@ -918,6 +975,7 @@ TEST_F(ServerTest, Http400HtmlError)
     </p>
 )"  },
     { /* url */ "/ROOT%23%3F/search?pattern=foo",
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "400-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "400-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "invalid-request", "params" : { "url" : "/ROOT%23%3F/search?pattern=foo" } } }, { "p" : { "msgid" : "too-many-books", "params" : { "LIMIT" : "3", "NB_BOOKS" : "4" } } } ] })" &&
       expected_body==R"(
     <h1>Invalid request</h1>
     <p>
@@ -931,6 +989,7 @@ TEST_F(ServerTest, Http400HtmlError)
     // Testing of translation
     { /* url */ "/ROOT%23%3F/search?content=zimfile&userlang=test",
       expected_page_title=="[I18N TESTING] Invalid request ($400 fine must be paid)" &&
+      expected_kiwix_response_data==R"({ "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "400-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "400-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "invalid-request", "params" : { "url" : "/ROOT%23%3F/search?content=zimfile&userlang=test" } } }, { "p" : { "msgid" : "no-query", "params" : { } } } ] })" &&
       expected_body==R"(
     <h1>[I18N TESTING] -400 karma for an invalid request</h1>
     <p>
@@ -1036,7 +1095,10 @@ TEST_F(ServerTest, 500)
   <head>
     <meta content="text/html;charset=UTF-8" http-equiv="content-type" />
     <title>Internal Server Error</title>
-
+    <script>
+      window.KIWIX_RESPONSE_TEMPLATE = )" + ERROR_HTML_TEMPLATE_JS_STRING + R"(;
+      window.KIWIX_RESPONSE_DATA = { "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "500-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "500-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "500-page-text", "params" : { } } }, { "p" : { "msgid" : "non-translated-text", "params" : { "MSG" : "Entry redirect_loop.html is a redirect entry." } } } ] };
+    </script>
   </head>
   <body>
     <h1>Internal Server Error</h1>
@@ -1054,6 +1116,7 @@ TEST_F(ServerTest, 500)
   const auto r = zfs1_->GET("/ROOT%23%3F/content/poor/A/redirect_loop.html");
   EXPECT_EQ(r->status, 500);
   EXPECT_EQ(r->body, expectedBody);
+  EXPECT_EQ(r->get_header_value("Content-Type"), "text/html; charset=utf-8");
   }
 }
 

test/server_search.cpp

@@ -1509,7 +1509,10 @@ std::string expectedConfusionOfTonguesErrorHtml(std::string url)
   <head>
     <meta content="text/html;charset=UTF-8" http-equiv="content-type" />
     <title>Invalid request</title>
-
+    <script>
+      window.KIWIX_RESPONSE_TEMPLATE = )" + ERROR_HTML_TEMPLATE_JS_STRING + R"(;
+      window.KIWIX_RESPONSE_DATA = { "CSS_URL" : false, "PAGE_HEADING" : { "msgid" : "400-page-heading", "params" : { } }, "PAGE_TITLE" : { "msgid" : "400-page-title", "params" : { } }, "details" : [ { "p" : { "msgid" : "invalid-request", "params" : { "url" : ")" + url + R"(" } } }, { "p" : { "msgid" : "confusion-of-tongues", "params" : { } } } ] };
+    </script>
   </head>
   <body>
     <h1>Invalid request</h1>

test/server_testing_tools.h

@@ -190,3 +190,5 @@ protected:
     zfs1_.reset();
   }
 };
+
+static const std::string ERROR_HTML_TEMPLATE_JS_STRING = R"("<!DOCTYPE html>\n<html xmlns="http://www.w3.org/1999/xhtml">\n  <head>\n    <meta content="text/html;charset=UTF-8" http-equiv="content-type" />\n    <title>{{PAGE_TITLE}}</title>\n{{#CSS_URL}}\n    <link type="text/css" href="{{{CSS_URL}}}" rel="Stylesheet" />\n{{/CSS_URL}}{{#KIWIX_RESPONSE_DATA}}    <script>\n      window.KIWIX_RESPONSE_TEMPLATE = "{{KIWIX_RESPONSE_TEMPLATE}}";\n      window.KIWIX_RESPONSE_DATA = {{{KIWIX_RESPONSE_DATA}}};\n    </script>{{/KIWIX_RESPONSE_DATA}}\n  </head>\n  <body>\n    <h1>{{PAGE_HEADING}}</h1>\n{{#details}}\n    <p>\n      {{{p}}}\n    </p>\n{{/details}}\n  </body>\n</html>\n")";