libkiwix/src/server.cpp

/*
 * Copyright 2019 Matthieu Gautier <mgautier@kymeria.fr>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU  General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 */

#define KIWIX_MIN_CONTENT_SIZE_TO_DEFLATE 100

#ifdef _WIN32

#if !defined(__MINGW32__) && (_MSC_VER < 1600)
#include "stdint4win.h"
#endif
#include <winsock2.h>
#include <ws2tcpip.h>  // otherwise socklen_t is not a recognized type
//#include <Windows.h> // otherwise int is not a recognized type
// typedef int off_t;
// typedef SSIZE_T ssize_t;
typedef UINT64 uint64_t;
typedef UINT16 uint16_t;
extern "C" {
#include <microhttpd.h>
}

#endif

#include "tools/otherTools.h"
#include "tools/pathTools.h"
#include "tools/regexTools.h"
#include "tools/stringTools.h"
#include "library.h"
#include "name_mapper.h"
#include "entry.h"
#include "searcher.h"
#include "search_renderer.h"
#include "opds_dumper.h"

#include <zim/uuid.h>

#include <mustache.hpp>

#include <pthread.h>
//#include <stdio.h>
//#include <stdlib.h>
#include <atomic>
#include <string>
#include <vector>
#include <chrono>
#include "kiwixlib-resources.h"

#ifndef _WIN32
//#include <arpa/inet.h>
//#include <ifaddrs.h>
//#include <netdb.h>
//#include <stdint.h>
//#include <sys/socket.h>
//#include <netinet/in.h>
#endif

#include "server.h"
#include "server/request_context.h"
#include "server/response.h"

#ifdef interface
#undef interface
#endif


#define MAX_SEARCH_LEN 140

namespace kiwix {

static IdNameMapper defaultNameMapper;

static int staticHandlerCallback(void* cls,
                                 struct MHD_Connection* connection,
                                 const char* url,
                                 const char* method,
                                 const char* version,
                                 const char* upload_data,
                                 size_t* upload_data_size,
                                 void** cont_cls);


class InternalServer {
  public:
    InternalServer(Library& library,
                   NameMapper* nameMapper,
                   int port,
                   std::string root,
                   int nbThreads,
                   bool verbose,
                   bool withTaskbar,
                   bool withLibraryButton);
    virtual ~InternalServer() = default;

    int handlerCallback(struct MHD_Connection* connection,
                        const char* url,
                        const char* method,
                        const char* version,
                        const char* upload_data,
                        size_t* upload_data_size,
                        void** cont_cls);
    bool start();
    void stop();

  private:
    Response handle_request(const RequestContext& request);
    Response build_404(const RequestContext& request, const std::string& zimName);
    Response build_homepage(const RequestContext& request);
    Response handle_skin(const RequestContext& request);
    Response handle_catalog(const RequestContext& request);
    Response handle_meta(const RequestContext& request);
    Response handle_search(const RequestContext& request);
    Response handle_suggest(const RequestContext& request);
    Response handle_random(const RequestContext& request);
    Response handle_content(const RequestContext& request);

    kainjow::mustache::data get_default_data();
    Response get_default_response();

    int m_port;
    std::string m_root;
    int m_nbThreads;
    std::atomic_bool m_verbose;
    bool m_withTaskbar;
    bool m_withLibraryButton;
    struct MHD_Daemon* mp_daemon;

    Library& m_library;
    NameMapper* mp_nameMapper;
};


Server::Server(Library& library, NameMapper* nameMapper) :
  m_library(library),
  mp_nameMapper(nameMapper),
  mp_server(nullptr)
{
}

Server::~Server() = default;

bool Server::start() {
  mp_server.reset(new InternalServer(
    m_library,
    mp_nameMapper,
    m_port,
    m_root,
    m_nbThreads,
    m_verbose,
    m_withTaskbar,
    m_withLibraryButton));
  return mp_server->start();
}

void Server::stop() {
  mp_server->stop();
  mp_server.reset(nullptr);
}


InternalServer::InternalServer(Library& library,
                               NameMapper* nameMapper,
                               int port,
                               std::string root,
                               int nbThreads,
                               bool verbose,
                               bool withTaskbar,
                               bool withLibraryButton) :
  m_port(port),
  m_root(root),
  m_nbThreads(nbThreads),
  m_verbose(verbose),
  m_withTaskbar(withTaskbar),
  m_withLibraryButton(withLibraryButton),
  mp_daemon(nullptr),
  m_library(library),
  mp_nameMapper(nameMapper ? nameMapper : &defaultNameMapper)
{}

bool InternalServer::start() {
 // TODO Readd selection of the interface
#ifdef _WIN32
  int flags = MHD_USE_SELECT_INTERNALLY;
#else
  int flags = MHD_USE_POLL_INTERNALLY;
#endif
  if (m_verbose.load())
    flags |= MHD_USE_DEBUG;

  mp_daemon = MHD_start_daemon(flags,
                            m_port,
                            NULL,
                            NULL,
                            &staticHandlerCallback,
                            this,
                            MHD_OPTION_THREAD_POOL_SIZE, m_nbThreads,
                            MHD_OPTION_END);
  if (mp_daemon == nullptr) {
    std::cerr << "Unable to instantiate the HTTP daemon. The port " << m_port
              << " is maybe already occupied or need more permissions to be open. "
                 "Please try as root or with a port number higher or equal to 1024."
              << std::endl;
    return false;
  }
  return true;
}

void InternalServer::stop()
{
  MHD_stop_daemon(mp_daemon);
}

static int staticHandlerCallback(void* cls,
                                 struct MHD_Connection* connection,
                                 const char* url,
                                 const char* method,
                                 const char* version,
                                 const char* upload_data,
                                 size_t* upload_data_size,
                                 void** cont_cls)
{
  InternalServer* _this = static_cast<InternalServer*>(cls);

  return _this->handlerCallback(connection,
                                url,
                                method,
                                version,
                                upload_data,
                                upload_data_size,
                                cont_cls);
}

int InternalServer::handlerCallback(struct MHD_Connection* connection,
                                    const char* url,
                                    const char* method,
                                    const char* version,
                                    const char* upload_data,
                                    size_t* upload_data_size,
                                    void** cont_cls)
{
  auto start_time = std::chrono::steady_clock::now();
  if (m_verbose.load() ) {
    printf("======================\n");
    printf("Requesting : \n");
    printf("full_url  : %s\n", url);
  }
  RequestContext request(connection, m_root, url, method, version);

  if (m_verbose.load() ) {
    request.print_debug_info();
  }
  /* Unexpected method */
  if (request.get_method() != RequestMethod::GET
   && request.get_method() != RequestMethod::POST) {
    printf("Reject request because of unhandled request method.\n");
    printf("----------------------\n");
    return MHD_NO;
  }

  auto response = handle_request(request);

  auto ret = response.send(request, connection);
  auto end_time = std::chrono::steady_clock::now();
  auto time_span = std::chrono::duration_cast<std::chrono::duration<double>>(end_time - start_time);
  if (m_verbose.load()) {
    printf("Request time : %fs\n", time_span.count());
    printf("----------------------\n");
  }
  return ret;
}


Response InternalServer::handle_request(const RequestContext& request)
{
  if (! request.is_valid_url())
    return build_404(request, "");

  if (kiwix::startsWith(request.get_url(), "/skin/"))
    return handle_skin(request);

  if (startsWith(request.get_url(), "/catalog"))
    return handle_catalog(request);

  if (request.get_url() == "/meta")
    return handle_meta(request);

  if (request.get_url() == "/search")
    return handle_search(request);

  if (request.get_url() == "/suggest")
    return handle_suggest(request);

  if (request.get_url() == "/random")
    return handle_random(request);

  return handle_content(request);
}

kainjow::mustache::data InternalServer::get_default_data()
{
  kainjow::mustache::data data;
  data.set("root", m_root);
  return data;
}

Response InternalServer::get_default_response()
{
  return Response(m_root, m_verbose.load(), m_withTaskbar, m_withLibraryButton);
}


Response InternalServer::build_404(const RequestContext& request,
                                   const std::string& humanReadableBookId)
{
  kainjow::mustache::data results;
  results.set("url", request.get_full_url());

  auto response = get_default_response();
  response.set_template(RESOURCE::templates::_404_html, results);
  response.set_mimeType("text/html");
  response.set_code(MHD_HTTP_NOT_FOUND);
  response.set_compress(true);
  response.set_taskbar(humanReadableBookId, "");

  return response;
}

Response InternalServer::build_homepage(const RequestContext& request)
{
  auto data = get_default_data();

  kainjow::mustache::data books{kainjow::mustache::data::type::list};
  for (auto& bookId: m_library.getBooksIds()) {
    auto& currentBook = m_library.getBookById(bookId);
    if ( currentBook.getPath().empty()
      || m_library.getReaderById(bookId) == nullptr) {
      continue;
    }

    kainjow::mustache::data book;
    book.set("name", currentBook.getHumanReadableIdFromPath());
    book.set("title", currentBook.getTitle());
    book.set("description", currentBook.getDescription());
    book.set("articleCount", beautifyInteger(currentBook.getArticleCount()));
    book.set("mediaCount", beautifyInteger(currentBook.getMediaCount()));
    books.push_back(book);
  }

  data.set("books", books);

  auto response = get_default_response();
  response.set_template(RESOURCE::templates::index_html, data);
  response.set_mimeType("text/html; charset=utf-8");
  response.set_compress(true);
  response.set_taskbar("", "");
  return response;
}

Response InternalServer::handle_meta(const RequestContext& request)
{
  std::string humanReadableBookId;
  std::string bookId;
  std::string meta_name;
  try {
    humanReadableBookId = request.get_argument("content");
    bookId = mp_nameMapper->getIdForName(humanReadableBookId);
    meta_name = request.get_argument("name");
  } catch (const std::out_of_range& e) {
    return build_404(request, humanReadableBookId);
  }

  auto reader = m_library.getReaderById(bookId);
  if (reader == nullptr) {
    return build_404(request, humanReadableBookId);
  }

  std::string content;
  std::string mimeType = "text";

  if (meta_name == "title") {
    content = reader->getTitle();
  } else if (meta_name == "description") {
    content = reader->getDescription();
  } else if (meta_name == "language") {
    content = reader->getLanguage();
  } else if (meta_name == "name") {
    content = reader->getName();
  } else if (meta_name == "tags") {
    content = reader->getTags();
  } else if (meta_name == "date") {
    content = reader->getDate();
  } else if (meta_name == "creator") {
    content = reader->getCreator();
  } else if (meta_name == "publisher") {
    content = reader->getPublisher();
  } else if (meta_name == "favicon") {
    reader->getFavicon(content, mimeType);
  } else {
    return build_404(request, humanReadableBookId);
  }

  auto response = get_default_response();
  response.set_content(content);
  response.set_mimeType(mimeType);
  response.set_compress(false);
  response.set_cache(true);
  return response;
}

Response InternalServer::handle_suggest(const RequestContext& request)
{
  if (m_verbose.load()) {
    printf("** running handle_suggest\n");
  }

  std::string content;
  std::string mimeType;
  unsigned int maxSuggestionCount = 10;
  unsigned int suggestionCount = 0;
  std::string suggestion;

  std::string humanReadableBookId;
  std::string bookId;
  std::string term;
  try {
    humanReadableBookId = request.get_argument("content");
    bookId = mp_nameMapper->getIdForName(humanReadableBookId);
    term = request.get_argument("term");
  } catch (const std::out_of_range&) {
    return build_404(request, humanReadableBookId);
  }

  if (m_verbose.load()) {
    printf("Searching suggestions for: \"%s\"\n", term.c_str());
  }

  auto reader = m_library.getReaderById(bookId);
  kainjow::mustache::data results{kainjow::mustache::data::type::list};

  bool first = true;
  if (reader != nullptr) {
    /* Get the suggestions */
    reader->searchSuggestionsSmart(term, maxSuggestionCount);
    while (reader->getNextSuggestion(suggestion)) {
      kainjow::mustache::data result;
      result.set("label", suggestion);
      result.set("value", suggestion);
      result.set("first", first);
      first = false;
      results.push_back(result);
      suggestionCount++;
    }
  }

  /* Propose the fulltext search if possible */
  if (reader->hasFulltextIndex()) {
    kainjow::mustache::data result;
    result.set("label", "containing '" + term + "'...");
    result.set("value", term);
    result.set("first", first);
    results.push_back(result);
  }

  auto data = get_default_data();
  data.set("suggestions", results);

  auto response = get_default_response();
  response.set_template(RESOURCE::templates::suggestion_json, data);
  response.set_mimeType("application/json; charset=utf-8");
  response.set_compress(true);
  return response;
}

Response InternalServer::handle_skin(const RequestContext& request)
{
  if (m_verbose.load()) {
    printf("** running handle_skin\n");
  }

  auto response = get_default_response();
  auto resourceName = request.get_url().substr(1);
  try {
    response.set_content(getResource(resourceName));
  } catch (const ResourceNotFound& e) {
    return build_404(request, "");
  }
  response.set_mimeType(getMimeTypeForFile(resourceName));
  response.set_compress(true);
  response.set_cache(true);
  return response;
}

Response InternalServer::handle_search(const RequestContext& request)
{
  if (m_verbose.load()) {
    printf("** running handle_search\n");
  }

  std::string content;
  std::string mimeType;
  std::string httpRedirection;

  std::string humanReadableBookId;
  std::string patternString;
  std::string bookId;
  try {
    humanReadableBookId = request.get_argument("content");
    bookId = mp_nameMapper->getIdForName(humanReadableBookId);
  } catch (const std::out_of_range&) {}

  try {
    patternString = request.get_argument("pattern");
  } catch (const std::out_of_range&) {}

  /* Retrive geo search */
  bool has_geo_query = false;
  float latitude = 0;
  float longitude = 0;
  float distance = 0;
  try {
    latitude = request.get_argument<float>("latitude");
    longitude = request.get_argument<float>("longitude");
    distance = request.get_argument<float>("distance");
    has_geo_query = true;
  } catch(const std::out_of_range&) {}
    catch(const std::invalid_argument&) {}

  std::shared_ptr<Reader> reader(nullptr);
  try {
    reader = m_library.getReaderById(bookId);
  } catch (const std::out_of_range&) {}

  /* Try first to load directly the article */
  if (reader != nullptr && !patternString.empty()) {
    std::string patternCorrespondingUrl;
    auto variants = reader->getTitleVariants(patternString);
    auto variantsItr = variants.begin();

    while (patternCorrespondingUrl.empty() && variantsItr != variants.end()) {
      try {
        auto entry = reader->getEntryFromTitle(*variantsItr);
        entry = entry.getFinalEntry();
        patternCorrespondingUrl = entry.getPath();
        break;
      } catch(kiwix::NoEntry& e) {
        variantsItr++;
      }
    }

    /* If article found then redirect directly to it */
    if (!patternCorrespondingUrl.empty()) {
      auto response = get_default_response();
      response.set_redirection(m_root + "/" + humanReadableBookId + "/" + patternCorrespondingUrl);
      return response;
    }
  }

  /* Make the search */
  auto response = get_default_response();
  response.set_mimeType("text/html; charset=utf-8");
  response.set_taskbar(humanReadableBookId, reader ? reader->getTitle() : "");
  response.set_compress(true);

  Searcher searcher;
  if (reader) {
    searcher.add_reader(reader.get());
  } else {
    if (humanReadableBookId.empty()) {
      for (auto& bookId: m_library.filter(kiwix::Filter().local(true).valid(true))) {
        auto currentReader = m_library.getReaderById(bookId);
        if (currentReader) {
          searcher.add_reader(currentReader.get());
        }
      }
    } else {
      response.set_content("<!DOCTYPE html>\n<html><head><meta content=\"text/html;charset=UTF-8\" http-equiv=\"content-type\" /><title>Fulltext search unavailable</title></head><body><h1>Not Found</h1><p>There is no article with the title <b>\"" + kiwix::encodeDiples(patternString) + "\"</b> and the fulltext search engine is not available for this content.</p></body></html>");
      response.set_code(MHD_HTTP_NOT_FOUND);
    }
  }

  if (!patternString.empty() || has_geo_query) {
    auto start = 0;
    try {
      start = request.get_argument<unsigned int>("start");
    } catch (const std::exception&) {}
    auto end = 25;
    try {
      end = request.get_argument<unsigned int>("end");
    } catch (const std::exception&) {}
    if (start>end) {
      auto tmp = start;
      start = end;
      end = tmp;
    }
    if (end > start + MAX_SEARCH_LEN) {
      end = start + MAX_SEARCH_LEN;
    }

    /* Get the results */
    try {
      if (patternString.empty()) {
        searcher.geo_search(latitude, longitude, distance,
                             start, end, m_verbose.load());
      } else {
        searcher.search(patternString,
                         start, end, m_verbose.load());
      }
      SearchRenderer renderer(&searcher, mp_nameMapper);
      renderer.setSearchPattern(patternString);
      renderer.setSearchContent(humanReadableBookId);
      renderer.setProtocolPrefix(m_root + "/");
      renderer.setSearchProtocolPrefix(m_root + "/search?");
      response.set_content(renderer.getHtml());
    } catch (const std::exception& e) {
      std::cerr << e.what() << std::endl;
    }
  } else {
    response.set_content("<!DOCTYPE html>\n<html><head><meta content=\"text/html;charset=UTF-8\" http-equiv=\"content-type\" /><title>Fulltext search unavailable</title></head><body><h1>Not Found</h1><p>There is no article with the title <b>\"" + kiwix::encodeDiples(patternString) + "\"</b> and the fulltext search engine is not available for this content.</p></body></html>");
    response.set_code(MHD_HTTP_NOT_FOUND);
  }
  return response;
}

Response InternalServer::handle_random(const RequestContext& request)
{
  if (m_verbose.load()) {
    printf("** running handle_random\n");
  }

  std::string humanReadableBookId;
  std::string bookId;
  try {
    humanReadableBookId = request.get_argument("content");
    bookId = mp_nameMapper->getIdForName(humanReadableBookId);
  } catch (const std::out_of_range&) {
    return build_404(request, humanReadableBookId);
  }

  auto reader = m_library.getReaderById(bookId);
  if (reader == nullptr) {
    return build_404(request, humanReadableBookId);
  }

  try {
    auto entry = reader->getRandomPage();
    entry = entry.getFinalEntry();
    auto response = get_default_response();
    response.set_redirection(m_root + "/" + humanReadableBookId + "/" + kiwix::urlEncode(entry.getPath()));
    return response;
  } catch(kiwix::NoEntry& e) {
    return build_404(request, humanReadableBookId);
  }
}

Response InternalServer::handle_catalog(const RequestContext& request)
{
  if (m_verbose.load()) {
    printf("** running handle_catalog");
  }

  std::string host;
  std::string url;
  try {
    host = request.get_header("Host");
    url  = request.get_url_part(1);
  } catch (const std::out_of_range&) {
    return build_404(request, "");
  }

  auto response = get_default_response();
  if (url == "searchdescription.xml") {
    response.set_template(RESOURCE::opensearchdescription_xml, get_default_data());
    response.set_mimeType("application/opensearchdescription+xml");
  } else {
    zim::Uuid uuid;
    kiwix::OPDSDumper opdsDumper;
    opdsDumper.setRootLocation(m_root);
    opdsDumper.setSearchDescriptionUrl("catalog/searchdescription.xml");
    opdsDumper.setId(kiwix::to_string(uuid));
    opdsDumper.setLibrary(&m_library);
    response.set_mimeType("application/atom+xml;profile=opds-catalog;kind=acquisition; charset=utf-8");
    std::vector<std::string> bookIdsToDump;
    if (url == "root.xml") {
      opdsDumper.setTitle("All zims");
      uuid = zim::Uuid::generate(host);

      bookIdsToDump = m_library.filter(kiwix::Filter().valid(true).local(true).remote(true));
    } else if (url == "search") {
      std::string query;
      std::string language;
      std::vector<std::string> tags;
      std::vector<std::string>  noTags;
      size_t count(10);
      size_t startIndex(0);
      try {
        query = request.get_argument("q");
      } catch (const std::out_of_range&) {}
      try {
        language = request.get_argument("lang");
      } catch (const std::out_of_range&) {}
      try {
        count = extractFromString<unsigned long>(request.get_argument("count"));
      } catch (...) {}
      try {
        startIndex = extractFromString<unsigned long>(request.get_argument("start"));
      } catch (...) {}
      try {
        tags = kiwix::split(request.get_argument("notag"), ";");
      } catch (...) {}
      try {
        noTags = kiwix::split(request.get_argument("notag"), ";");
      } catch (...) {}
      opdsDumper.setTitle("Search result for " + query);
      uuid = zim::Uuid::generate();
      bookIdsToDump = m_library.filter(
        kiwix::Filter().valid(true).local(true).remote(true)
          .query(query)
          .lang(language)
          .acceptTags(tags)
          .rejectTags(noTags)
        );
      auto totalResults = bookIdsToDump.size();
      bookIdsToDump.erase(bookIdsToDump.begin(), bookIdsToDump.begin()+startIndex);
      if (count>0 && bookIdsToDump.size() > count) {
        bookIdsToDump.resize(count);
      }
      opdsDumper.setOpenSearchInfo(totalResults, startIndex, bookIdsToDump.size());
    } else {
      return build_404(request, "");
    }

    response.set_content(opdsDumper.dumpOPDSFeed(bookIdsToDump));
  }

  response.set_compress(true);
  return response;
}

Response InternalServer::handle_content(const RequestContext& request)
{
  if (m_verbose.load()) {
    printf("** running handle_content\n");
  }

  std::string baseUrl;
  std::string content;
  std::string mimeType;

  kiwix::Entry entry;

  std::string humanReadableBookId;
  try {
    humanReadableBookId = request.get_url_part(0);
  } catch (const std::out_of_range& e) {
    return build_homepage(request);
  }
  if (humanReadableBookId.size() == 0)
    return build_homepage(request);

  std::string bookId;
  try {
    bookId = mp_nameMapper->getIdForName(humanReadableBookId);
  } catch (const std::out_of_range& e) {
    return build_404(request, humanReadableBookId);
  }

  auto reader = m_library.getReaderById(bookId);
  if (reader == nullptr) {
    return build_404(request, humanReadableBookId);
  }

  auto urlStr = request.get_url().substr(humanReadableBookId.size()+1);
  if (urlStr[0] == '/') {
    urlStr = urlStr.substr(1);
  }

  try {
    entry = reader->getEntryFromPath(urlStr);
    if (entry.isRedirect() || urlStr.empty()) {
      // If urlStr is empty, we want to mainPage.
      // We must do a redirection to the real page.
      entry = entry.getFinalEntry();
      auto response = get_default_response();
      response.set_redirection(m_root + "/" + humanReadableBookId + "/" +
        kiwix::urlEncode(entry.getPath()));
      return response;
    }
  } catch(kiwix::NoEntry& e) {
    if (m_verbose.load())
      printf("Failed to find %s\n", urlStr.c_str());

    return build_404(request, humanReadableBookId);
  }

  try {
    mimeType = entry.getMimetype();
  } catch (exception& e) {
    mimeType = "application/octet-stream";
  }

  if (m_verbose.load()) {
    printf("Found %s\n", urlStr.c_str());
    printf("mimeType: %s\n", mimeType.c_str());
  }

  if (mimeType.find("text/") != string::npos
      || mimeType.find("application/javascript") != string::npos
      || mimeType.find("application/json") != string::npos) {
    zim::Blob raw_content = entry.getBlob();
    content = string(raw_content.data(), raw_content.size());
    auto response = get_default_response();
    response.set_mimeType(mimeType);

    /* Special rewrite URL in case of ZIM file use intern *asbolute* url like
     * /A/Kiwix */
    if (mimeType.find("text/html") != string::npos) {
      content = replaceRegex(content,
                             "$1$2" + m_root + "/" + humanReadableBookId + "/$3/",
                             "(href|src)(=[\"|\']{0,1})/([A-Z|\\-])/");
      content = replaceRegex(content,
                             "$1$2" + m_root + "/" + humanReadableBookId + "/$3/",
                             "(@import[ ]+)([\"|\']{0,1})/([A-Z|\\-])/");
      response.set_taskbar(humanReadableBookId, reader->getTitle());
    } else if (mimeType.find("text/css") != string::npos) {
      content = replaceRegex(content,
                             "$1$2" + m_root + "/" + humanReadableBookId + "/$3/",
                             "(url|URL)(\\([\"|\']{0,1})/([A-Z|\\-])/");
    }
    response.set_content(content);
    response.set_compress(true);
    response.set_cache(true);
    return response;
  } else {
    int range_len;
    if (request.get_range().second == -1) {
       range_len = entry.getSize() - request.get_range().first;
    } else {
       range_len = request.get_range().second - request.get_range().first;
    }
    auto response = get_default_response();
    response.set_entry(entry);
    response.set_mimeType(mimeType);
    response.set_range_first(request.get_range().first);
    response.set_range_len(range_len);
    response.set_cache(true);
    return response;
  }
}

}