Better exception

CHANGES.rst

@@ -1,6 +1,10 @@
 1.4 (unreleased)
 ================
 
+- More explicit exception messages where the payload is 
+  sometimes considered if it can be presented properly (simple
+  body text or job error message). [#355]
+
 - we now ignore namespaces in xsi-type attributes; this is a lame fix
   for services like ESO's and MAST's TAP, which do not use canonical
   prefixes while astropy.utils.xml ignores namespaces. [#323]

pyvo/dal/adhoc.py

@@ -5,6 +5,7 @@
 import numpy as np
 import warnings
 import copy
+import requests
 from collections import OrderedDict
 
 from .query import DALResults, DALQuery, DALService, Record
@@ -247,7 +248,10 @@ def getdataset(self, timeout=None):
         try:
             url = next(self.getdatalink().bysemantics('#this')).access_url
             response = self._session.get(url, stream=True, timeout=timeout)
-            response.raise_for_status()
+            try:
+                response.raise_for_status()
+            except requests.RequestException as ex:
+                raise DALServiceError.from_except(ex, url)
             return response.raw
         except (DALServiceError, ValueError, StopIteration):
             # this should go to Record.getdataset()
@@ -563,8 +567,7 @@ def bysemantics(self, semantics, include_narrower=True):
                     additional_terms.extend(voc["terms"][term]["narrower"])
             core_terms = core_terms+additional_terms
 
-        semantics = set("#"+term for term in core_terms
-            ) | set(other_terms)
+        semantics = set("#"+term for term in core_terms) | set(other_terms)
         for record in self:
             if record.semantics in semantics:
                 yield record

pyvo/dal/exceptions.py

@@ -176,11 +176,18 @@ def from_except(cls, exc, url=None):
         for the given exception that represents the underlying cause.
         """
         if isinstance(exc, requests.exceptions.RequestException):
-            message = str(exc)
             try:
-                code = exc.response.status_code
+                response = exc.response
             except AttributeError:
-                code = 0
+                response = None
+            code = 0
+            if response is not None:
+                code = response.status_code
+            message = str(exc)
+            content_type = response.headers.get('content-type', None)
+            if content_type and 'text/plain' in content_type:
+                message = '{} for {}'.format(response.text, url)
+            # TODO votable handling
 
             return DALServiceError(message, code, exc, url)
         elif isinstance(exc, Exception):

pyvo/dal/query.py

@@ -322,7 +322,7 @@ def __init__(self, votable, url=None, session=None):
 
         if self._status[0].lower() == "overflow":
             warn("Partial result set. Potential causes MAXREC, async storage space, etc.",
-                 category=DALOverflowWarning);
+                 category=DALOverflowWarning)
 
         self._resultstable = self._findresultstable(votable)
         if not self._resultstable:
@@ -771,8 +771,11 @@ def getdataset(self, timeout=None):
             response = self._session.get(url, stream=True, timeout=timeout)
         else:
             response = self._session.get(url, stream=True)
+        try:
+            response.raise_for_status()
+        except requests.RequestException as ex:
+            raise DALServiceError.from_except(ex, url)
 
-        response.raise_for_status()
         return response.raw
 
     def cachedataset(self, filename=None, dir=".", timeout=None, bufsize=None):

pyvo/dal/tap.py

@@ -821,7 +821,8 @@ def raise_if_error(self):
             if theres an error
         """
         if self.phase in {"ERROR", "ABORTED"}:
-            raise DALQueryError("Query Error", self.phase, self.url)
+            msg = self._job._message if self._job and self._job._message else ''
+            raise DALQueryError("Query Error: " + msg, self.url)
 
     def fetch_result(self):
         """

pyvo/dal/tests/test_tap.py

@@ -13,6 +13,8 @@
 import requests_mock
 
 from pyvo.dal.tap import escape, search, AsyncTAPJob, TAPService
+from pyvo.dal import DALQueryError
+
 from pyvo.io.uws import JobFile
 from pyvo.io.uws.tree import Parameter, Result
 
@@ -98,7 +100,11 @@ def create(self, request, context):
         job = JobFile()
         job.version = "1.1"
         job.jobid = newid
-        job.phase = 'PENDING'
+        if 'test_erroneus_submit.non_existent' in request.text:
+            job.phase = 'ERROR'
+            job.message = 'test_erroneus_submit.non_existent not found'
+        else:
+            job.phase = 'PENDING'
         job.quote = Time.now() + TimeDelta(1, format='sec')
         job.creationtime = Time.now()
         job.executionduration = TimeDelta(3600, format='sec')
@@ -439,6 +445,15 @@ def test_submit_job(self):
         job.wait()
         job.delete()
 
+    @pytest.mark.usefixtures('async_fixture')
+    def test_erroneus_submit_job(self):
+        service = TAPService('http://example.com/tap')
+        job = service.submit_job(
+            "SELECT * FROM test_erroneus_submit.non_existent")
+        with pytest.raises(DALQueryError) as e:
+            job.raise_if_error()
+        assert 'test_erroneus_submit.non_existent not found' in str(e)
+
     @pytest.mark.usefixtures('async_fixture')
     def test_submit_job_case(self):
         """Test using mixed case in the QUERY parameter to a job.