web.isgd() now throws an error when it cant shorten a URL

plugins/util/web.py

@@ -11,16 +11,25 @@ yql_env = "http://datatables.org/alltables.env"
 YQL = yql.Public()
 
 
-def query(query, params={}):
-    """ runs a YQL query and returns the results """
-    return YQL.execute(query, params, env=yql_env)
+class ShortenError(Exception):
+    def __init__(self, code, text):
+        self.code = code
+        self.text = text
+
+    def __str__(self):
+        return self.text
 
 
 def isgd(url):
     """ shortens a URL with the is.gd PAI """
     url = urlnorm.normalize(url.encode('utf-8'), assume_scheme='http')
-    params = urllib.urlencode({'format': 'simple', 'url': url})
-    return http.get("http://is.gd/create.php?%s" % params)
+    params = urllib.urlencode({'format': 'json', 'url': url})
+    request = http.get_json("http://is.gd/create.php?%s" % params)
+
+    if "errorcode" in request:
+        raise ShortenError(request["errorcode"], request["errormessage"])
+    else:
+        return request["shorturl"]
 
 
 def haste(text):
@@ -28,3 +37,8 @@ def haste(text):
     page = http.get(paste_url + "/documents", post_data=text)
     data = json.loads(page)
     return("%s/%s.txt" % (paste_url, data['key']))
+
+
+def query(query, params={}):
+    """ runs a YQL query and returns the results """
+    return YQL.execute(query, params, env=yql_env)