Q:

How to get list of documents in ArangoDB?

For accessing to collection content I need to know {collection-name} and {document-key}. 
How I can get list of all documents with their {document-key} in ArangoDB with http?

A:

In docs there is a GET /_api/document request which will retrieve all documents from collection. If you specify type=key query string parameter then you will get response with an array of document keys.

