Error out more usefully from formparams when required parameters are missing.

[wrw.git] / wrw / util.py

diff --git a/wrw/util.py b/wrw/util.py
index 6368b18..64b820f 100644 (file)
--- a/wrw/util.py
+++ b/wrw/util.py
@@ -1,5 +1,5 @@
 import inspect
-import req, dispatch, session, form
+import req, dispatch, session, form, resp
 
 def wsgiwrap(callable):
     def wrapper(env, startreq):
@@ -16,6 +16,9 @@ def formparams(callable):
             for arg in list(args):
                 if arg not in spec.args:
                     del args[arg]
+        for i in xrange(len(spec.args) - len(spec.defaults)):
+            if spec.args[i] not in args:
+                raise resp.httperror(400, "Missing parameter", ("The query parameter `", resp.h.code(spec.args[i]), "' is required but not supplied."))
         return callable(**args)
     return wrapper
 
@@ -34,6 +37,37 @@ def persession(data = None):
         return wrapper
     return dec
 
+class preiter(object):
+    __slots__ = ["bk", "bki", "_next"]
+    end = object()
+    def __init__(self, real):
+        self.bk = real
+        self.bki = iter(real)
+        self._next = None
+        self.next()
+
+    def __iter__(self):
+        return self
+
+    def next(self):
+        if self._next is self.end:
+            raise StopIteration()
+        ret = self._next
+        try:
+            self._next = next(self.bki)
+        except StopIteration:
+            self._next = self.end
+        return ret
+
+    def close(self):
+        if hasattr(self.bk, "close"):
+            self.bk.close()
+
+def pregen(callable):
+    def wrapper(*args, **kwargs):
+        return preiter(callable(*args, **kwargs))
+    return wrapper
+
 class sessiondata(object):
     @classmethod
     def get(cls, req, create = True):