George Kalpakas d8d276c245 docs(docs-infra): update preview server docs to account for recent changes (#25671 )

Mostly (but not exclusively) a follow-up to #23576.

PR Close #25671

2018-09-26 15:26:19 -07:00

Overview - HTTP Status Codes

This is a list of all the possible HTTP status codes returned by the nginx and preview servers, along with a brief explanation of what they mean:

`http://.ngbuilds.io/`

307 (Temporary Redirect): All non-HTTPS requests. 308 (Permanent Redirect) would be more appropriate, but is not supported by all agents (e.g. cURL).

200 (OK): File was found or URL was rewritten to /index.html (i.e. all paths that have no . in final segment).
403 (Forbidden): Trying to access a sub-directory.
404 (Not Found): File not found.

200 (OK): Whether the PR can have a public preview (based on its author, label, changed files). Response type: JSON Response format:
```
{
  canHavePublicPreview: boolean,
  reason: string | null,
}
```
405 (Method Not Allowed): Request method other than GET.

201 (Created): Build deployed successfully and is publicly available.
202 (Accepted): Build not automatically verifiable. Stored for later deployment (after re-verification).
204 (No Content): Build was not successful, so no further action is being taken.
400 (Bad Request): Invalid payload.
403 (Forbidden): Unable to talk to 3rd-party APIs.
405 (Method Not Allowed): Request method other than POST.
409 (Conflict): Request to overwrite existing (public or non-public) directory (e.g. deploy existing build or change PR visibility when the destination directory does already exist).

200 (OK): The server is healthy (i.e. up and running and processing requests).

200 (OK): Request processed successfully. Processing may or may not have resulted in further actions.
400 (Bad Request): No payload or no number field in payload.
405 (Method Not Allowed): Request method other than POST.
409 (Conflict): Request to overwrite existing (public or non-public) directory (i.e. directories for both visibilities exist). (Normally, this should not happen.)

404 (Not Found): Request not matched by the above rules.
500 (Internal Server Error): Error while processing a request matched by the above rules.