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Snowcrash parser harness

API Blueprint Parser

Drafter is complex builder of API Blueprint. Internally it uses Snowcrash library, reference API Blueprint parser.

API Blueprint is Web API documentation language. You can find API Blueprint documentation on the API Blueprint site.

Drafter also provides the user ability to select the type of the output. There are two possible values:

  • API Elements Parse Result: Parse Result is defined in API Elements according to Parse Result Namespace.
  • Normal AST Parse Result: Parse Result defined by the API Blueprint AST Parse Result. The AST is deprecated and only available in the Drafter command line tool.

By default, Drafter assumes the Refract Parse Result.

Both the types of Parse Results are available in two different serialization formats, YAML and JSON. YAML is the default for the CLI.



OS X using Homebrew:

$ brew install drafter

AUR package for Arch Linux.

Other systems refer to installation notes.


Drafter is both a library and a command line tool.

Command line tool

The command line tool allows you to parse a blueprint and/or check the validity of a blueprint.

$ cat << 'EOF' > blueprint.apib
# My API
## GET /message
+ Response 200 (text/plain)

        Hello World!

$ drafter blueprint.apib
element: "parseResult"
    element: "category"
        - "api"
      title: "My API"

See parse feature for the details on using the drafter command line tool.


#include <drafter/drafter.h>

The header itself is annotated with comments. C API unit tests provide more examples.

Parse API Blueprint into API Elements

The drafter_parse_blueprint_to function translates a buffered API blueprint into API Elements, serialized into one of its supported serialization formats.

drafter_error drafter_parse_blueprint_to(
    const char* source,
    char** out,
    const drafter_parse_options* parse_opts,
    const drafter_serialize_options* serialize_opts);

Given a pointer to a UTF-8 encoded c-string,

const char* blueprint =
  "# My API\n"
  "## GET /message\n"
  "+ Response 200 (text/plain)\n"
  "      Hello World!\n";
Serialized as YAML

Without options, the resulting API Elements is serialized as YAML.

char* yamlApie = NULL;
if (DRAFTER_OK == drafter_parse_blueprint_to(blueprint, &yamlApie, NULL, NULL)) {
    printf("%s\n", yamlApie);

Serialized as JSON

Tweaking drafter_serialize_options allows serialization into JSON.

drafter_serialize_options* serialize_options = drafter_init_serialize_options();
drafter_set_format(serialize_options, DRAFTER_SERIALIZE_JSON);

char* jsonApie = NULL;
if (DRAFTER_OK == drafter_parse_blueprint_to(blueprint, &jsonApie, NULL, serialize_options)) {
    printf("%s\n", jsonApie);


Validate API Blueprint

API Blueprint can be validated via drafter_check_blueprint.

drafter_error drafter_check_blueprint(
    const char* source,
    drafter_result** res,
    const drafter_parse_options* parse_opts);
Simple validation

The return value of drafter_check_blueprint indicates validation success.

drafter_result* result = NULL;
if (DRAFTER_OK == drafter_check_blueprint(blueprint, result)) {

Access warnings and errors

After running drafter_check_blueprint, the result parameter is set to reference an API Element containing validation warnings or errors.

Because the result is an API Element - drafter_result - it can be serialized as such.

drafter_result* result = NULL;
drafter_check_blueprint(blueprint, result);

if(result) {
    char* yamlApie = drafter_serialize(result, NULL);
    printf("%s\n", yamlApie);


Serialization of API Elements as JSON is achieved by tweaking drafter_serialize_options as discussed here.


Building Drafter will require a modern C++ compiler and CMake. The following compilers are tested and known to work:

Compiler Minimum Version
Clang 4.0
GCC 5.3
MSVC++ 2015

The following steps can be used to build and install Drafter:

  1. Download a stable release of Drafter (release tarballs can be found in GitHub Releases):

    $ curl -OL <url to drafter release from GitHub releases>
    $ tar xvf drafter.tar.gz
    $ cd drafter

    Alternatively, you can clone the source repository, for example:

    $ git clone --recursive
    $ cd drafter
  2. Build & Install Drafter:

    POSIX (macOS/Linux):

    $ mkdir build
    $ cd build
    $ cmake ..
    $ make
    $ [sudo] make install

    NOTE: You can use cmake -DCMAKE_INSTALL_PREFIX="$HOME/.local .. if you don't want a system wide install.


    > mkdir build
    > cd build
    > cmake ..
    > cmake --build . --target drafter --config Release

    On Windows, drafter.exe can be found inside src\Release

  3. You can now use Drafter CLI and library:

    $ drafter --help


Drafter bindings in other languages:

CLI Wrapper


Fork & Pull Request

If you want to create a binding for Drafter please refer to the Writing a Binding article.


MIT License. See the LICENSE file.