Lately I have been planning a number of migrations to move small/big companies from TFS on-premises to Visual Studio Team Services (VSTS).
There are a number of options to migrate data from TFS to VSTS, but option 3 [high-fidelity database migration] is unfortunately not yet available. So, most of the time I still use custom/third-party tooling to perform the migration which is not always straightforward and may be very time-consuming.
One serious issue that popped up in a migration towards VSTS (using the TFS Integration Tools), was that the inline images in the Description field (or other html fields) of migrated work items were not properly migrated. The inline images are actually still referring to the old TFS on-premises environment because the html value of the Description field contains an <img> element with a source set to http://<tfs-on-prem>:8080/tfs/<tpc>/workitemtracking/v1.0/attachfilehandler.ashx?filenameguid=<guid>&filename=<filename>.png.
As a result, all inline images are only stored in the old TFS environment and they have not been uploaded to VSTS. The html value of the Description field has been migrated as-is. Initially you might not notice this after the migration of the selected work items because as long as the old TFS environment is still available, the inline image will be displayed. But what if the old TFS environment has been archived/destroyed?
To correct this and to upload the original images to VSTS, I have written some code (TFS API) to loop over the VSTS work items to detect image links to the old TFS environment. Using the source link of the original image, I can download the image to my local disk and upload it as an attachment to the VSTS work item. Finally, I’m replacing the original image source link with the new VSTS image link. Good to know is that once in-line images are detected inside the html field, those images are stored on the server and the temporary image file attachments may be deleted as well.