ENH: refs #254. Adding ajaxWebApi for calling the web api via ajax.

Author: cpatrick

modules/api/public/js/common/common.ajaxapi.js

@@ -0,0 +1,102 @@
+var ajaxWebApi = {};
+
+/**
+ * Wraps the jQuery ajax function with mechanisms to handle
+ * authentication to the web API and parsing and logging of the
+ * response object, including error handling
+ * Parameters:
+ *   method: Web API method to call (such as midas.bitstream.list)
+ *   [authenticate]: defaults to true. If set to false, won't login
+ *   [args]: Key=value arguments to the web API method, delimited with &
+ *   [success]: Function to be called when this function is finished (one 
+ *              arg, the response json object)
+ *   [error]: Function to be called if the request fails (one arg, the
+ *            response json object)
+ *   [complete]: Function to be called when done with the request, whether or
+ *               not it was successful
+ *   [log]: jQuerified DOM object representing the log area where output will
+ *          be written. Default behavior is alert() in error conditions.
+ */
+ajaxWebApi.ajax = function(params)
+{
+  if(!params.method)
+    {
+    alert('ajaxWebApi.ajax: method parameter not set');
+    return;
+    }
+
+  this._webApiCall(params);
+}
+
+/** Internal function.  Do not call directly. */
+ajaxWebApi._webApiCall = function(params)
+{
+  if(!params.args)
+    {
+    params.args = 'useSession=true';
+    }
+  else
+    {
+    params.args += '&useSession=true';
+    }
+
+
+  $.ajax({
+    type: 'POST',
+    url: json.global.webroot + '/api/json?method=' + params.method,
+    data: params.args,
+    dataType: 'json',
+    success: function(retVal) {
+      if(params.complete)
+        {
+        params.complete();
+        }
+      if(retVal.stat == 'fail')
+        {
+        ajaxWebApi.logError(params.method + '?' + params.args + ' failed: ' + retVal.message, params.log);
+        if(params.error)
+          {
+          params.error(retVal);
+          }
+        return;
+        }
+      //TODO detect invalid (expired) token.  If so, set our token = '' and try again
+      if(params.success)
+        {
+        params.success(retVal);
+        }
+      },
+    error: function() {
+      ajaxWebApi.logError('Ajax call to web API returned an error (' +
+          json.global.webroot + '/api/json' + '?' + params.method + '&' + params.args + ')', params.log);
+      if(params.complete)
+        {
+        params.complete();
+        }
+      }
+  });
+}
+
+ajaxWebApi.logMessage = function(text, log)
+{
+  if(log)
+    {
+    log.append('<span style="color:black;">' + text + '</span><br>');
+    }
+  else
+    {
+    alert(text);
+    }
+}
+
+ajaxWebApi.logError = function(text, log)
+{
+  if(log)
+    {
+    log.append('<span style="color:red;">Error: ' + text + '</span><br>');
+    }
+  else
+    {
+    alert('Error: ' + text);
+    }
+}