1This file describes steps and files needed when adding a new API to Chrome.
2Before you start coding your new API, though, make sure you follow the process
3described at:
4  http://www.chromium.org/developers/design-documents/extensions/proposed-changes/apis-under-development
5
6Two approaches are available for writing your API specification. The original
7approach relies on JSON specification files. The more recent and simpler system 
8uses Web IDL files, but does not yet support all the features of the JSON files.
9Discuss with a member of the extensions team (aa@chromium.org) before you decide
10which approach is better suited to your API.
11
12The following steps suppose you're writing an experimental API called "Foo".
13
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15APPROACH 1: JSON FILES
16
171) Write your API specification.
18Create "chrome/common/extensions/api/experimental_foo.json". For inspiration 
19look at the "app" API. Include descriptions fields to generate the
20documentation.
21
222) Add your API specification to api.gyp.
23Add "experimental_foo.json" to the "schema_files" section in
24"chrome/common/extensions/api/api.gyp".
25
263) Write the API function handlers.
27Create foo_api.cc and foo_api.h under "chrome/browser/extensions/api/foo". You
28should use the JSON Schema Compiler. Look at the "permissions_api.cc" for
29details on how to do that.
30
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32APPROACH 2: IDL FILES
33
341) Write your API specification.
35Create "chrome/common/extensions/api/experimental_foo.idl". For inspiration look
36at "alarms.idl". Include comments, they will be used to automatically generate
37the documentation.
38
392) Add your API specification to api.gyp.
40Add "experimental_foo.idl" to the "schema_files" section in
41"chrome/common/extensions/api/api.gyp".
42
433) Write the API function handlers.
44Create foo_api.cc and foo_api.h under "chrome/browser/extensions/api/foo". You
45should use the JSON Schema Compiler. Look at the "alarms_api.cc" for details on
46how to do that.
47
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49STEPS COMMON TO BOTH APPROACHES
50
516) Write support classes for your API
52If your API needs any support classes add them to
53"chrome/browser/extensions/api/foo". Some old APIs added their support classes
54directly to chrome/browser/extensions. Don't do that.
55
567) Update the project with your new files.
57The files you created in (3) and (5) should be added to
58"chrome/chrome_browser_extensions.gypi".
59
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61GENERATING DOCUMENTATION
62
638) Add a stub template in ../docs/templates/public corresponding to your API.
64See other templates for inspiration.
65
669) Run ../docs/templates/server2/preview.py to view the generated documentation.
67
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69WRITING TESTS
70
7112) Write a unit test for your API.
72Create "chrome/browser/extensions/api/foo/foo_api_unittest.cc" and test each of
73your API methods. See "alarms_api_unittest.cc" for details. Once done add your
74.cc to "chrome/chrome_tests.gypi".
75