I would check out the connect usage markdown document on github referenced above by Cole. It has details on getting decodes of the user and content guids, https://github.com/sol-eng/connect-usage.
Most everything will start to transition to app_guid (and GUID is actually available in the "INFO" tab for a given piece of content - see the bottom of this image).
I actually don't think the mapping is really exposed anywhere easy to access, or I'm just missing something obvious in the API guide. Where did you get the App ID that you are trying to map to a GUID? Or are you trying to go the other direction? Do you mind explaining a bit about what you're trying to do?
sorry for my late response; I havenot yet figured out a way to map them;
Is there a plan for such option in future connect release?
Yes, we would definitely love to address the issue you are facing. Do you mind clarifying for me where you are getting the App ID, though? It would be ideal to understand what your workflow is, so that any proposed solution would resolve the issue.
Hi Cole,
I have queried "v1/instrumentation/shiny/usage". The result set gives me an output with 'content_guid' and 'user_guid';
Next I have mapped user_guid with user_id (queried from "v1/users").
My final frame looks like below example:
app_guid and User_ID
yshao77691911 (username)
Awesome. And so what is your desired state? Are you trying to get the content information now?
Hi Cole,
I am looking for a frame which will have results with following components atleast:
Userid; App_ID; App_Name
And why do you need the app_id in your output? What are you using it for?
Hi Cole,
I dont need app_id. Basically I am looking for a frame which can show userid and appname; We may also plan for another frame like user_id, app_name, schedule_time....
if there is option to achieve this without app_id; then I am fine 
Yes! Awesome 
You want to take the app_guid you have and go to GET /content/. That should give you the app name. If you want to build a URL, you can do that with the GUID as well, in place of the APP ID.
https://docs.rstudio.com/connect/api/#getContent
For instance, for GUID ABCD, I could get the Connect dashboard at:
Is this API not available in 1.6.10? I am receiving error as I try to run GET command:
GET("https://rsconnectURL/api/v1/experimental/content", add_headers(Authorization = paste("Key", apiKey)))
GET("https://rsconnectURL/api/v1/experimental/content/xxxxxxx-guid-xxxxxx", add_headers(Authorization = paste("Key", apiKey)))
Error:
Date: 2019-02-28 19:24
Status: 404
Content-Type: text/plain
Size: 18 B
Oh sad. Yeah, I think this endpoint might have been released in 1.7.0 
Sorry about that! Any flexibility on updating? Lots of exciting stuff in that release! The blog post is here:
https://blog.rstudio.com/2019/01/17/announcing-rstudio-connect-1-7-0/