This product is concerned with the issuing of invitations to join an online group in bulk [1], using a CSV file submitted to a form. Most of the page is powered by JavaScript.

The admin_invite_csv.html form, in the Group context, takes a CSV file and invites each person in the file (one per row) to join the group. The work is done in two main steps — parsing and inviting — which is controlled by JavaScript.

In the CSV file each row represents a person, and each column represents a profile attribute. The form gs-group-member-invite-csv.json, in the group context [2], parses the information in the CSV file and returns a JSON object: a list of profile data. The JavaScript then handles the inviting.

The parsing form is a "JSON" form, as supplied by gs.content.form.api.json [4]. The HTTP PUT parses in a list of column identifiers and the CSV file, and a JSON object is returned. If successful the object is a list of profile-objects. If there is a problem then a JSON object is returned with status set to one of the following error numbers, and message set to a human readable message.

The inviting is actually carried out by gs.group.member.invite.json. If the CSV is fine then the JavaScript fires off invitation notifications provided by gs.group.member.invite.base. The invitation is responded to using one of the two pages in the gs.profile.invite module [3].

JavaScript is essential to the Invite by CSV system; without full compliance the page simply will not work. I decided to make the JavaScript a requirement because it drastically the system, reducing errors in my code, and drastically improves the usability. (The usability is far from good, but the earlier CSV Invite system would only show a spinner and generally end up showing a TCP Timeout error page.) The code, provided by the resource /++resource++gs-group-member-invite-csv.js, controls the marshalling of user-supplied data, a template generator, the parsing AJAX and the inviting AJAX. All are controlled by some connecting code.

There are two components to the user-supplied data:

• The CSV file (which we will ignore for now) and
• The columns.

The latter is supported by the JavaScript class GSInviteByCSVOptionalAttributes. The page and code provide a table at Twitter Bootstrap dropdown that allows the group administrator to select the optional attributes in the page. The same class can marshal the data out of the HTML-table (embedded in the page) and into a list of profile attributes and names. These are used by the template generator and parsing ajax.

The template-CSV generator is provided by the GSInviteByCSVTemplateGenerator class. It examines the profile-attributes that have been specified by the group administrator and then generates a data-URL. This URL is then set as the href for a (hidden) anchor element that is then added to a page. Finally, a click event is fired, which causes the browser to "download" the CSV template.

The JavaScript that powers the parsing AJAX is one of the reasons that only (relatively) new browsers support the Invite by CSV page. The class GSInviteByCSVParserAJAX makes use of the FormData [5] and File [6] APIs to marshal the data out of the form and to the parsing`_ form.

The same code examines the return value from the parser. If a problem was encountered then the error message is shown. Otherwise the inviting AJAX is called.

The JavaScript code that actually invites each person is provided by the GSInviteByCSVInviterAJAX class. It maintains the list of people that are yet to be invited, updates the progress bar when the inviting form responds, and (depending on the response) updates the New, Ignored or Error lists.

As is fairly standard for GroupServer JavaScript the page uses attributes of the <script> element to pass data (such as URLs and element selectors) to the JavaScript. As is also fairly standard, the JavaScript is only initialised after the window has raised the load event. Events are used to connect one sequence of events (parsing the file) with another (inviting the people).

Finally, the connecting the code is also used to reset the entire form when the group administrator clicks on the Reset button.

The template generator code, like much that is tricky with the Web, is helped by Stack Overflow.

• Code repository: https://github.com/groupserver/gs.group.member.invite.csv
• Questions and comments to http://groupserver.org/groups/development
• Report bugs at https://redmine.iopen.net/projects/groupserver