This commit adds an API endpoint for notifying the preview server about PR
updates (`/pr-updated`). According to the update, the preview server can take
several actions. Currently, it will only check and (if necessary) update the
PR's preview visibility (but more actions could be supported in the future).
The API can be used with an automatic trigger (e.g. a GitHub webhook) to
instantly update a PR's preview visibility when it changes.
Fixes#16526
Previously, there was a distinction between GET requests to invalid URLs and all
other requests. This was mainly because the upload-server only accepts GET
requests, but that is not a hard limitation and may change in the future.
Thus, it makes sense to return a 404 response for requests to invalid URLs
regardless of the method used.
Use the 7 first characters of the 40-chars long SHAs for shorter/cleaner URLs.
The collision probability is extremely low (since all SHAs are further
"namespaced" under the corresponding PR). In case of a collision, the second PR
will not be deployed, in order to avoid overwriting the original build.
(This is a design decision to keep the implementation simple. It can be changed
later if necessary.)
Previously, when trying to upload the build artifacts for a PR/SHA that was
already successfully deployed (e.g. when re-running a Travis job), the preview
server would return a 403 and the build would fail.
Since we have other mechanisms to verify that the PR author is trusted and the
artifacts do indeed come from the specified PR and since the new artifacts
should be the same with the already deployed ones (same SHA), there is no reason
to fail the build. The preview server will reject the request with a special
HTTP status code (409 - Conflict), which the `deploy-preview` script will
recognize and exit with 0.
Georgios Kalpakas