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| stage | group | info |
|---|---|---|
| none | unassigned | To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/product/ux/technical-writing/#assignments |
JSON development guidelines
At GitLab we handle a lot of JSON data. To best ensure we remain performant when handling large JSON encodes or decodes, we use our own JSON class instead of the default methods.
Gitlab::Json
This class should be used in place of any calls to the default JSON class,
.to_json calls, and the like. It implements the majority of the public
methods provided by JSON, such as .parse, .generate, .dump, etc, and
should be entirely identical in its response.
The difference being that by sending all JSON handling through Gitlab::Json
we can change the gem being used in the background. We use oj
instead of the json gem, which uses C extensions and is therefore notably
faster.
This class came into existence because, due to the age of the GitLab application,
it was proving impossible to just replace the json gem with oj by default because:
- The number of tests with exact expectations of the responses.
- The subtle variances between different JSON processors, particularly around formatting.
The Gitlab::Json class takes this into account and can
vary the adapter based on the use case, and account for outdated formatting
expectations.
Gitlab::Json::PrecompiledJson
This class is used by our hooks into the Grape framework to ensure that already-generated JSON is not then run through JSON generation a second time when returning the response.
Gitlab::Json::LimitedEncoder
This class can be used to generate JSON but fail with an error if the
resulting JSON would be too large. The default limit for the .encode
method is 25 MB, but this can be customized when using the method.