[server] Add source_by_eid and source_by_uri methods to repository
Most of the times we only need to retrieve one source (either by uri or eid)
and querying sources_by_eid and sources_by_uri properties on repository just
for one item is costly. So these methods query what's needed. We issue a
ValueError (instead of KeyError for sources_by_{eid,uri} dict) in case the key
is not found.
Tutorials
~~~~~~~~~
We present a few tutorials of different levels. The blog building
tutorial introduces one smoothly to the basic concepts.
Then there is a photo gallery construction tutorial which highlights
more advanced concepts such as unit tests, security settings,
migration scripts.
.. toctree::
:maxdepth: 1
base/index
advanced/index
tools/windmill.rst
textreports/index
dataimport/index