Enabled "manifestFirst" doesn't load resources defined in sap.ui5

[boghyon]

OpenUI5 version: All

URL (minimal example if possible): https://embed.plnkr.co/4mURwe/
(Update 2017.04.22: Added mandatory attributes in the app descriptor)

Steps to reproduce the problem:

1. Define any CSS or JS resources in the sap.ui5 namespace of app descriptor
2. Enable manifestFirst either in the bootstrap configuration or in the component factory
3. If available, remove manifest: "json" from the component metadata in order to avoid loading the file twice.

What is the expected result?
CSS and JS files are loaded and applied.

What happens instead?
Requests for those files aren't even sent.

Any other information? (attach screenshot if possible)
I couldn't find any mention about this behavior in the documentation. The CSS and JS resources gets loaded when manifest: "json" is defined in the component metadata. But this will send another request to manifest.json even if the descriptor was loaded already through manifestFirst.

[Shtilianova]

I've created a internal incident 1770165096. You can check its status on GitHub.

[matz3]

Your manifest.json is not valid.
The mandatory sap.app/id is missing, see:
https://openui5.hana.ondemand.com/#docs/guide/be0cf40f61184b358b5faedaec98b2da.html

This is why the file is loaded twice when using manifestFirst as the manifest can't be mapped to the corresponding component. If manifest: "json" is not provided it can still not use it as the Component needs to declare that it is using a manifest.

[boghyon]

@matz3 Ahh, I see. Thanks for pointing this out! I didn't see the connection between sap.app/id and the component name. Anyhow, I should have added the id anyway since it's marked as mandatory.

[boghyon]

@matz3 Sorry, I overlooked that even after adding all the mandatory attributes (such as sap.app/id with the corresponding component name) and enabling component metadata, I'm still getting the same manifest.json file twice. This can be also seen in this ComponentManifestFirst test after reloading the page and pressing the "Load Component" button:

The ComponentMetadata doesn't seem to check whether manifest.json has been already loaded before or not. As I understood, I shouldn't remove manifest: "json" to avoid this behavior. Did I misconfigure or misunderstand something?

[matz3]

@boghyon you are right. The file is loaded twice in this case.

The first request is triggered via the manifestFirst option which will load the manifest for the instance that is about to be created. This manifest object is also assigned to that instance allowing to load a different manifest (e.g. with different configuration) via the manifestUrl option (manifestFirst does the same as manifestUrl, just with the default URL).

The second request is triggered via sap.ui.core.ComponentMetadata which is statically created for the component class. This is mainly required for compatibility reasons with other use cases. In your case it won't be used by the component instance at all, as it has it's own manifest object already.

The reason why there are two requests is because this scenario has been optimized for the productive use where the Component-preload.js (404 in your case) also contains the manifest.json file. This way the additional request would be prevented, resulting into two requests:

1. manifest.json
2. Component-preload.js (contains Component.js, manifest.json, ...)

To create the Component-preload.js file you can use the openui5_preload Grunt task:
https://github.com/SAP/grunt-openui5#openui5_preload

Here is a sample app using that task:
https://github.com/SAP/openui5-sample-app

[boghyon]

@matz3 I see. Thanks for the clarification. It would be nice if the behavior you described is in the doc somewhere where manifestFirst is mentioned. I think there were and will be more devs wondering why the request to the same file is sent twice (in case no Component-preload.js is available) which might even lead them to remove the manifest assignment in the component metadata (like I did before :P).

[boghyon]

Just to note down for other readers what I observed: Since 1.54.0 (and without Component-preload.js), the manifest file is not loaded twice anymore but only when there was a name provided in the component creation. E.g.:

sap.ui.component({
  name: "...",
  manifest: true
})

If a URL is given instead (manifest: "myPath.json"), the manifest file is loaded twice again.

[matz3]

@boghyon that's right. We've optimized the manifest loading internally to share it with the ComponentMetadata class.
Sorry for not updating this issue. This was done with 0e271c9.

If a URL is given instead (manifest: "myPath.json"), the manifest file is loaded twice again.

Yes, this is my design as the manifest loaded from a different location could have a different content than the one loaded from the default location. So we only share it in case the resulting URL would be the same.