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)
Veloman Yunkan
Matthieu Gautier