# Qualifier Lexicon

This lexicon defines standard qualifier names that servers
**MAY** support in the `Qualifier` message to facilitate interoperability.

The following standard qualifier `name`s are defined:

* `resource_type`: This describes the type of resource.

  File assests should use an existing [media type](https://www.iana.org/assignments/media-types/media-types.xhtml).

  Git repositories should use `application/x-git`.
  
  Example:
  ```json
  // (FetchDirectoryRequest proto)
  {
    "uris": [
      "https://github.com/bazelbuild/remote-apis.git"
    ],
    "qualifiers": [
      {
        "name": "resource_type",
        "value": "application/x-git"
      }
    ]
  }
  ```   

* `checksum.sri`: The value represents a [Subresource Integrity](https://www.w3.org/TR/SRI/)
  checksum of the content.

  Example:
  ```json
  // (FetchBlobRequest proto)
  {
    "uris": [
      "https://github.com/bazelbuild/remote-apis/archive/v2.0.0.tar.gz"
    ],
    "qualifiers": [
      {
        "name": "checksum.sri",
        "value": "sha384-G9d9sKLNRfeFfGn1mnVXeJzXSbkCsYt11kl5hJnHpdzfVuLIuruIDnrs/lZyB4Gs"
      }
    ]
  }
  ```

* `directory`: This is the relative path of a subdirectory of the resource.  There should
  be no trailing `/`.

  Example:
  ```json
  // (FetchDirectoryRequest proto)
  {
    "uris": [
      "https://github.com/bazelbuild/remote-apis.git"
    ],
    "qualifiers": [
      {
        "name": "directory",
        "value": "build/bazel/remote/execution/v2"
      }
    ]
  }
  ```

* `vcs.branch`: This is the name of the branch under source control management

  Example:
  ```json
  // (FetchDirectoryRequest proto)
  {
    "uris": [
      "https://github.com/bazelbuild/remote-apis.git"
    ],
    "qualifiers": [
      {
        "name": "vcs.branch",
        "value": "master"
      }
    ]
  }
  ```

* `vcs.commit`: The value is the identity of a specific version of the content
  under source control management.  For git this is a commit-ish, for subversion
  this is a revision, for example.

  Example:
  ```json
  // (FetchDirectoryRequest proto)
  {
    "uris": [
      "https://github.com/bazelbuild/remote-apis.git"
    ],
    "qualifiers": [
      {
        "name": "vcs.commit",
        "value": "b5123b1bb2853393c7b9aa43236db924d7e32d61"
      }
    ]
  }
  ```