recipe/simplehttpserver: fix application/x-www-form-urlencoded POST on py3

In deploy test, this recipe is used with url encoded POST [1], but the
test only tested multipart encoded POSTs. In python 3, they are different,
with multipart POSTs, FieldStorage values are bytes, but with url encoded
POSTs, the values are string.

This small server from the recipe only supported multipart POSTs, this
change add support for url encoded POSTs.

[1]: https://lab.nexedi.com/nexedi/slapos/blob/dd7038feab70866e54028de89d0e0e1017fc276c/software/erp5testnode/testsuite/deploy-test/deploy-script-controller#L86

slapos/recipe/simplehttpserver/simplehttpserver.py

@@ -36,6 +36,15 @@ class ServerHandler(SimpleHTTPRequestHandler):
     SimpleHTTPRequestHandler.do_GET(self)
 
   def do_POST(self):
+    """Write to a file on the server.
+
+    request keys:
+      path: the path of the file
+      content: content of the file
+      clear: (0|1 default 1) overwrite the file if 1
+
+    request can be encoded as application/x-www-form-urlencoded or multipart/form-data
+    """
     logging.info('%s - POST: %s \n%s' % (self.client_address[0], self.path, self.headers))
     if self.restrictedRootAccess():
       return
@@ -46,14 +55,20 @@ class ServerHandler(SimpleHTTPRequestHandler):
       environ={'REQUEST_METHOD': 'POST',
                'CONTENT_TYPE': self.headers['Content-Type']}
     )
-    name = form['path'].value.decode('utf-8')
-    content = form['content'].value
-    method = 'ab'
-    if 'clear' in form and form['clear'].value == '1':
-      method = 'wb'
-    self.writeFile(name, content, method)
+
+    file_content = form['content'].value
+    file_path = form['path'].value
+    if form['content'].file:
+      # post data as multipart/form-data , values are bytes
+      file_path = file_path.decode('utf-8')
+    else:
+      # application/x-www-form-urlencoded , values are str
+      file_content = file_content.encode('utf-8')
+    file_open_mode = 'wb' if ('clear' in form and form['clear'].value in ('1', b'1')) else 'ab'
+
+    self.writeFile(file_path, file_content, file_open_mode)
     self.respond(200, type=self.headers['Content-Type'])
-    self.wfile.write(b"Content written to %s" % str2bytes(name))
+    self.wfile.write(b"Content written to %s" % str2bytes(file_path))
 
   def writeFile(self, filename, content, method='ab'):
     file_path = os.path.abspath(os.path.join(self.document_path, filename))

slapos/test/recipe/test_simplehttpserver.py

@@ -71,22 +71,43 @@ class SimpleHTTPServerTest(unittest.TestCase):
           'server did not start.\nout: %s error: %s' % self.process.communicate())
     self.assertIn('Directory listing for /', resp.text)
 
+    # post with multipart/form-data encoding
     resp = requests.post(
         server_base_url,
         files={
-            'path': 'hello.txt',
-            'content': b'hello',
+            'path': 'hello-form-data.txt',
+            'content': 'hello-form-data',
         },
     )
     self.assertEqual(resp.status_code, requests.codes.ok)
+    self.assertEqual(resp.text, 'Content written to hello-form-data.txt')
     with open(
         os.path.join(self.base_path, self.recipe.options['path'],
-                     'hello.txt')) as f:
-      self.assertEqual(f.read(), 'hello')
+                     'hello-form-data.txt')) as f:
+      self.assertEqual(f.read(), 'hello-form-data')
 
-    self.assertIn('hello.txt', requests.get(server_base_url).text)
+    self.assertIn('hello-form-data.txt', requests.get(server_base_url).text)
     self.assertEqual(
-        requests.get(server_base_url + '/hello.txt').text, 'hello')
+        requests.get(server_base_url + '/hello-form-data.txt').text, 'hello-form-data')
+
+    # post as application/x-www-form-urlencoded
+    resp = requests.post(
+        server_base_url,
+        data={
+            'path': 'hello-form-urlencoded.txt',
+            'content': 'hello-form-urlencoded',
+        },
+    )
+    self.assertEqual(resp.status_code, requests.codes.ok)
+    with open(
+        os.path.join(self.base_path, self.recipe.options['path'],
+                     'hello-form-urlencoded.txt')) as f:
+      self.assertEqual(f.read(), 'hello-form-urlencoded')
+
+    self.assertIn('hello-form-urlencoded.txt', requests.get(server_base_url).text)
+    self.assertEqual(resp.text, 'Content written to hello-form-urlencoded.txt')
+    self.assertEqual(
+        requests.get(server_base_url + '/hello-form-urlencoded.txt').text, 'hello-form-urlencoded')
 
     # incorrect paths are refused
     for path in '/hello.txt', '../hello.txt':