fix: send languages() request as GET, not POST (#449)

argostranslate/apis.py

@@ -79,7 +79,7 @@ def languages(self):
 
         url_params = parse.urlencode(params)
 
-        req = request.Request(url, data=url_params.encode())
+        req = request.Request(url, data=url_params.encode(), method="GET")
 
         response = request.urlopen(req)
 

tests/test_apis.py

@@ -0,0 +1,45 @@
+import json
+from io import BytesIO
+from unittest.mock import patch
+
+from argostranslate.apis import LibreTranslateAPI
+
+
+def _fake_response(payload):
+    return BytesIO(json.dumps(payload).encode())
+
+
+class TestLibreTranslateAPIRequestMethods:
+    """LibreTranslate's `/languages` endpoint only accepts GET; `/translate`
+    and `/detect` accept POST. `urllib.request.Request` defaults to POST
+    whenever a `data` body is set, for every HTTP method except GET - so
+    each call must set the right method explicitly rather than relying on
+    the default, or the server rejects it with 405 METHOD NOT ALLOWED. See
+    #449.
+    """
+
+    def test_languages_request_is_get(self):
+        api = LibreTranslateAPI("https://example.org/")
+        with patch("argostranslate.apis.request.urlopen") as urlopen:
+            urlopen.return_value = _fake_response([{"code": "en", "name": "English"}])
+            api.languages()
+        req = urlopen.call_args[0][0]
+        assert req.get_method() == "GET"
+
+    def test_translate_request_is_post(self):
+        api = LibreTranslateAPI("https://example.org/")
+        with patch("argostranslate.apis.request.urlopen") as urlopen:
+            urlopen.return_value = _fake_response({"translatedText": "hola"})
+            api.translate("hello", "en", "es")
+        req = urlopen.call_args[0][0]
+        assert req.get_method() == "POST"
+
+    def test_detect_request_is_post(self):
+        api = LibreTranslateAPI("https://example.org/")
+        with patch("argostranslate.apis.request.urlopen") as urlopen:
+            urlopen.return_value = _fake_response(
+                [{"confidence": 0.9, "language": "en"}]
+            )
+            api.detect("hello")
+        req = urlopen.call_args[0][0]
+        assert req.get_method() == "POST"