Currently, there are no rest APIs available to download a Jira attachment. Can somebody explain me how to create a custom rest endpoint to download an attachment by calling the rest call and giving the parameters issue id and attachment id?
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You can use the "get content" REST call to get the attachment - see https://developer.atlassian.com/cloud/jira/platform/rest/v3/api-group-issue-attachments/#api-group-issue-attachments but you do need to do a bit of messing around to get the file name and work out what the attachment id is (you'll need to do that messing around in a REST endpoint too)
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