During work on the kiwix-serve front-end, the edit-save-test cycle is
a multistep procedure:
1. build and install libkiwix
2. build kiwix-tools
3. run kiwix-serve
4. reload the web-page in the browser
When making changes in static resources that are served by kiwix-serve
unmodified, the steps 1-3 can be eliminated if kiwix-serve is capable of
serving resources from the file-system. This commit adds such a
functionality to kiwix-serve. Now, if during startup of kiwix-serve the
environment variable `KIWIX_SERVE_CUSTOMIZED_RESOURCES` is defined it is
assumed to point to a file where every line has the following format:
URL MIMETYPE RESOURCE_FILE_PATH
When a request is received by kiwix-serve and its URL matches any of the
URLs read from the customized resource file, then the resource data is
read from the respective file RESOURCE_FILE_PATH and served with
mime-type MIMETYPE.
Though this feature was introduced in order to facilitate the
development of the iframe-based content viewer, it can also be useful to
users who would like to customize the kiwix-serve front-end on their own
(without re-building all of kiwix-serve).
There is some overlap with a feature of the kiwix-compile-resources
script that also allows to override resources. The differences are:
1. The new way of customizing front-end resources has all such resources
listed in a text file and there is a single environment variable
from which the path of that file is read. kiwix-compile-resources
associates a separate environment variable with each resource.
2. The new way uses regular paths to identify a resource. The
kiwix-compile-resources method encodes the resource path by replacing
any non-alphanumeric characters (including the path separator) with
underscores (so that the resulting resource identifier can be used
to construct the name of the environment variable controlling that
resource).
3. The new method allows adding new front-end resources. The old method
only allows to modify existing resources.
4. The new method allows (actually requires) to specify the URL at which
the overriden resource should be served (similarly, the MIME-type can/must
be specified, too). The old method only allows to override the contents of
a resource.
5. The new method only allows to override front-end resources that are
served without any preprocessing by kiwix-serve at runtime. The old
method allows to override template resources as well (note that
internationalization/translation resources cannot be overriden using the
old method, either).
If we keep a reference to a `Reader` it is better to (share) owning
the reference. Else the reader may be deleted after we create the searcher.
This is especially the case now we are creating the `Reader` at demand
and we don't store it in the library's cache.
We have to reuse the query the user give us to generate the
pagination links.
At search result rendering step we don't have access to the query object.
The best place to know which arguments are used to select books
(and so which arguments to keep in the pagination links) is when we
parse the query to select books.
Fix tests (pagination links) with book selector other than "books.id="
(pattern=jazz&books.query.lang=eng)
libzim's search is not thread safe (mainly because xapian is not).
So we must protect our search objects from multi thread calls.
The best way to do this is to associate a mutex to the `zim::Searcher`
and lock the searcher each time we access object derivated from the
searcher (search, results, iterator, ...)
When ConcurrentCache store a shared_ptr we may have shared_ptr in used
while the ConcurrentCache has drop it.
When we "recreate" a value to put in the cache, we don't want to recreate
it, but copying the shared_ptr in use.
To do so we use a (unlimited) store of weak_ptr (aka `WeakStore`)
Every created shared_ptr added to the cache has a weak_ptr ref also stored
in the WeakStore, and we check the WeakStore before creating the value.
The prefix will be used to parse a "query to select book" in different context.
For now we have only one context : selecting books for the catalog search.
But we will want to select books to do fulltext search on them
(will be done in later commit)
- Throw a exception if we cannot extract from string.
(We throw the same exception as `std::sto*`)
- Add a specialization to extract string from string
- Add some unit test
The story of search_results.css
static/skin/search_results.css was extracted from
static/templates/no_search_result.html before the latter was dropped.
static/templates/no_search_result.html in turn seems to be a copied and
edited version of static/templates/search_result.html.
In the context of exploratory work on the internationalization of
kiwix-serve (PR #679) I noticed duplication of inline CSS across those
two templates and intended to eliminated it. That goal was not fully
accomplished (static/templates/search_result.html remained untouched)
because by that time PR #679 grew too big and the efforts were diverted
into splitting it into smaller ones. Thus search_results.css slipped
into one of those small PRs, without making much sense because nothing
really justifies preserving custom CSS in the "Fulltext search unavailable"
error page.
At the same time, it served as the only case where a link to a cacheable
resource is generated in C++ code (rather than found in a template).
This poses certain problems to the handling of cache-ids. A workaround
is to expel the URL into a template so that it is processed by
`kiwix-resources`. This commit merely demonstrates that solution. But
whether it should be preserved (or rather the "Fulltext search
unavailable" page should be deprived of CSS) is questionable.
In the absence of the "userlang" query parameter in the URL, the value
of the "Accept-Language" header is used. However, it is assumed that
"Accept-Language" specifies a single language (rather than a comma
separated list of languages possibly weighted with quality values).
Example:
Accept-Language: fr
// should work
Accept-Language: fr-CH, fr;q=0.9, en;q=0.8, de;q=0.7, *;q=0.5
// The requested language will be considered to be
// "fr-CH, fr;q=0.9, en;q=0.8, de;q=0.7, *;q=0.5".
// The i18n code will fail to find resources for such a language
// and will use the default "en" instead.
At this point a potential issue has been revealed. Now we produce
the final HTML via 2-level template expansion
1. Render parameterized messages
2. Render the HTML template
In which templates we should use double mustache "{{}}" (HTML-escaping)
tags and where we may use triple mustache "{{{}}}" (non-escaping) tags?
Introduced a new resource compiler script kiwix-compile-i18n that
processes i18n string data stored in JSON files and generates sorted C++
tables of string keys and values for all languages.
The "Fulltext search unavailable" error page is now generated using the
static/templates/error.html template. Also added two test cases checking
that error page.
404.html no longer contains anything specific to the 404 error and will
henceforth serve (with some enhancements) as a general purpose error
page template.
It is better to directly try to get the `Search` from the cache instead
of getting the `Searcher` first which could be useless in Search already
exist.
SearchInfo is a small helper structure to store information about the
queried search. It regroup already existing information (`patternString`,
geo query, ...) in one structure.
It is also used as key in the cache instead of using a generated string.
Matthieu Gautier
Veloman Yunkan