Merge pull request #6 from edx-solutions/mjevtic/documentation

Documention on css changes and validation

README.md

@@ -75,6 +75,25 @@ If you have not installed the xblock-sdk in the active virtualenv,
 you might also have to prepend `PYTHONPATH=".:/path/to/xblock"` to the command above.
 (`/path/to/xblock` is the path to the xblock-sdk, where the workbench resides).
 
+Changes to be documented
+------------------------
+
+1. Calendar width is set to 100% of parent element's width; this optimizes the display of google document content within the LMS user interface
+2. Max width of Google images is set to 100% to prevent images from overflowing outside the parent element's boundaries
+3. Since Google WordProcessing documents and Spreadsheets don't allow users to explicitly define width and height, their width is set to 100%. Also, min height is set to 450px, so that documents and/or spreadsheets with larger number of rows are displayed in their natural size. Overflow scroll is automatically turned on when the height of the document becomes larger than the height of the parent.
+
+Validation
+----------
+
+Each time a character is added to or removed from Google Calendar ID, validation takes place.
+Analogically, validation takes place for embedded code of Google Drive File.
+
+1. Google calendar IDs are being validated against a regular expression. IDs must contain at least one '@' character, with at least one character on each side of it, ie. 'a@a'.
+
+2. Embedded code of Google Drive file is being validated on the server side, by checking the status code of the HTTP response.
+   Since error status codes start with 400, it's assumed that each status code that's larger than or equal to 400 states that file is invalid.
+   If for any reason exception occurs while getting an HTTP response, error code is returned, thus overriding default signalization that is invoked by edx platform when the 500 status code is reported.
+
 License
 -------