CapPaste: add method to find if a paste is suitable for the backend

Basic support in pastoob added (there is no way yet to change the
default options).
Backends support the "public/private" requirement.

weboob/applications/pastoob/pastoob.py

@@ -84,12 +84,26 @@ class Pastoob(ReplApplication):
             with open(filename) as fp:
                 contents = fp.read()
 
-        # chose a random backend from the ones able to satisfy our requirements
-        accepted_backends = [backend for backend in self.weboob.iter_backends()]
-        backend = choice(accepted_backends)
+        # get and sort the backends able to satisfy our requirements
+        params = self._get_params()
+        backends = {}
+        for backend in self.weboob.iter_backends():
+            score = backend.can_post(**params)
+            if score:
+                backends.setdefault(score, []).append(backend)
+        # select a random backend from the best scores
+        if len(backends):
+            backend = choice(backends[max(backends.keys())])
+        else:
+            print >>sys.stderr, 'No suitable backend found.'
+            return 1
 
         p = backend.new_paste(_id=None)
+        p.public = params.get('public')
         p.title = os.path.basename(filename)
         p.contents = contents
         backend.post_paste(p)
         print 'Successfuly posted paste: %s' % p.page_url
+
+    def _get_params(self):
+        return {'public': True}

weboob/backends/pastealacon/backend.py

@@ -43,6 +43,11 @@ class PastealaconBackend(BaseBackend, ICapPaste):
     def new_paste(self, *args, **kwargs):
         return PastealaconPaste(*args, **kwargs)
 
+    def can_post(self, public=None):
+        if public is False:
+            return 0
+        return 1
+
     def get_paste(self, _id):
         with self.browser:
             return self.browser.get_paste(_id)

weboob/backends/pastealacon/test.py

@@ -79,3 +79,7 @@ class PastealaconTest(BackendTest):
         # same even with correct domain (IDs are numeric)
         assert self.backend.get_paste('http://pastealacon.com/nJG9ZFG8') is None
         assert self.backend.get_paste('nJG9ZFG8') is None
+
+    def test_can_post(self):
+        assert 0 == self.backend.can_post(public=False)
+        assert 1 == self.backend.can_post(public=True)

weboob/backends/pastebin/backend.py

@@ -47,6 +47,9 @@ class PastebinBackend(BaseBackend, ICapPaste):
     def new_paste(self, *args, **kwargs):
         return PastebinPaste(*args, **kwargs)
 
+    def can_post(self, public=None):
+        return 1
+
     def get_paste(self, _id):
         with self.browser:
             return self.browser.get_paste(_id)

weboob/backends/pastebin/test.py

@@ -77,3 +77,8 @@ class PastebinTest(BackendTest):
     def test_checkurl(self):
         # call with an URL we can't handle with this backend
         assert self.backend.get_paste('http://pastealacon.com/1') is None
+
+    def test_can_post(self):
+        assert self.backend.can_post(public=None) > 0
+        assert self.backend.can_post(public=True) > 0
+        assert self.backend.can_post(public=False) > 0

weboob/capabilities/paste.py

@@ -64,6 +64,22 @@ class ICapPaste(IBaseCap):
         """
         raise NotImplementedError()
 
+    def can_post(self, public=None):
+        """
+        Checks if the paste can be pasted by this backend.
+        Some properties are considered required (public/private, max_age) while others
+        are just bonuses (language).
+
+        public: True must be public, False must be private, None do not care
+
+        A score of 0 means the backend is not suitable.
+        A score of 1 means the backend is suitable.
+        Higher scores means it is more suitable than others with a lower score.
+
+        @return int Score
+        """
+        raise NotImplementedError()
+
     def get_paste(self, url):
         """
         Get a Paste from an ID or URL.