What is updated when publishing a remote file?

When a remote dataset is updated using an automated publishing schedule, the behavior is different depending on the source file's type and location.

This article describes what happens when such a file is stored on an FTP server, is an ArcGIS file, or is available via HTTPS.

• If an existing file is modified, we will reprocess the entire file.

• If a file is added (without modifying the other files), only this file will be processed. In other words, the update is incremental.

• If there are no changes in the folder, the dataset is not reprocessed on publication.

• If there is a change in the file, the entire file will be reprocessed on publication (because the FTP source is a file and not a folder, it is not possible to use incremental mode).

• If no change, the dataset is not reprocessed on publication.

In the case of an ArcGIS source, we are unable to detect whether the file has been modified since the last publication. As such, the entire file will be systematically be processed and published.

Similar to the FTP case, we need to detect a change in the file's modification date. This can be checked via the "Etag" and "Last-modified" headers, and the "If-None-Match" and "If-Modified-Since" conditional requests.

• If the "Last-modified" header returned by the HTTP source changes with each request, for example, the detection will not work, resulting in the entire file being reprocessed.

• The "If-Modified-Since" conditional request must provide a response with a HTTP 200 status, only if the resource has been modified since the given date. If the resource has not been modified since then, the response must have an HTTP 304 status with no content.

• With "If-None-Match", the server returns the requested resource, with a status of 200, only if it does not have an ETag corresponding to those provided. For the other methods, the request will only be processed if the ETag of any existing resource does not match any of the listed values. When the condition fails for GET and HEAD methods, the server returns an HTTP 304 (Not Modified) status code.

  For more information: https://developer.mozilla.org/fr/docs/Web/HTTP/Headers/If-None-Match