Developer Callbacks

In a number of places, not least of which is the POST callback described above, you supply one or more callback URLs which are then used by the PhotoShow widgets to obtain information about the embedding site (e.g. available photos) or to send information back to the site (embedding code for the photoshow). These callbacks follow a consistent pattern as follows:

• The choice of GET/POST method is consistent with the action being taken, e.g. GET when retrieving information from the external site and POST when putting information back to it.
• Arguments to GET methods are passed as query params, POST calls have arguments passed as post values in the body of the HTTP post.
• If provided in the initial call to the embedding widget, any sessionKey and userId values will be included in the parameters to all callbacks.
• The response should be a block of XML the structure of which depends on the query. Details are given where each query is described and there is XML Schema for the responses in the Callback Schema document.