This document addresses hackers who wants to get involved in the framework development.


You can avoid installing the library if you export LD_LIBRARY_PATH to the build folder.

export LD_LIBRARY_PATH=build

./waf configure
./waf build


Code conventions

Valum uses the Vala compiler coding style and these rules are specifically highlighted:

  • tabs for indentation
  • spaces for alignment
  • 80 characters for comment block and 120 for code
  • always align blocks of assignation around = sign
  • remember that little space between a function name and its arguments
  • doclets should be aligned, grouped and ordered alphabetically

General strategies

Produce minimal headers, especially if the response has an empty body as every byte will count.

Since GET handle HEAD as well, verifying the request method to prevent spending time on producing a body that won’t be considered is important.

res.headers.set_content_type ("text/html", null);

if (req.method == "HEAD") {
    size_t bytes_written;
    return res.write_head (out bytes_written);

return res.expand_utf8 ("<!DOCTYPE html><html></html>");

Use the construct block to perform post-initialization work. It will be called independently of how the object is constructed.

Tricky stuff

Many parts of the HTTP/1.1 specification is case-insensitive, in these cases, Soup.str_case_equal must be used to perform comparisons.

Try to stay by the book and read carefully the specification to ensure that the framework is semantically correct. In particular, the following points:

  • choice of a status code
  • method is case-sensitive
  • URI and query are automatically decoded by Soup.URI
  • headers and their parameters are case-insensitive
  • \r\n are used as newlines
  • do not handle Transfer-Encoding, except for the libsoup-2.4 implementation with steal_connection: at this level, it’s up to the HTTP server to perform the transformation

The framework should rely as much as possible upon libsoup-2.4 to ensure consistent and correct behaviours.


gcov is used to measure coverage of the tests on the generated C code. The results are automatically uploaded to Codecov on a successful build.

You can build Valum with gcov if you specify the appropriate CFLAGS and VALAFLAGS during the configuration step.

./waf configure CFLAGS='-fprovide-arcs -ftest-coverage' VALAFLAGS='--debug'
./waf build
./waf --alltests

During the execution of the tests, some files will be generated and can be inspected with the gcov utility.

cd build
gcov src/router.c.1.gcda

Would output something like:

File 'src/router.c'
Executed lines: 57.83% of 792
Creating 'router.c.gcov'

The generated router.c.gcov will contain detailed coverage information structured in three columns separated by a : character:

  • number of executions
  • line number
  • corresponding line of code

The number of executions can take the following values:

  • a - symbol means that the line is irrelevant (eg. comment)
  • ##### means that the line is uncovered
  • a positive integer indicates how many time the line has executed

Once you have identified an uncovered region, you can supply a test that covers that particular case and submit us a pull request on GitHub.


Valum is thoroughly tested for regression with the GLib.Test framework. Test cases are annotated with @since to track when a behaviour was introduced and guarantee its backward compatibility.

You can refer an issue from GitHub by calling Test.bug with the issue number.

Test.bug ("123");

Version bump

Most of the version substitutions is handled during the build, but some places in the code have to be updated manually:

  • VERSION and API_VERSION in wscript
  • GIR version annotations for all declared namespaces
  • version and release in docs/conf.py


To generate POT files, simply launch the following command:

ninja docs/pot

Then, move to the docs folder to update the translations for the language <lang>:

sphinx-intl update -p ../build/docs/pot -l <lang>

This should update the files located in po/<lang>/LC_MESSAGES. The docs can then be regenerated with the translations.

ninja docs/<lang>