Basic CSV export, refs #266

Tables and custom SQL query results can now be exported as CSV.

The easiest way to do this is to use the .csv extension, e.g.

	/test_tables/facet_cities.csv

By default this is served as Content-Type: text/plain so you can see it in
your browser. If you want to download the file (using text/csv and with an
appropriate Content-Disposition: attachment header) you can do so like this:

	/test_tables/facet_cities.csv?_dl=1

We link to the CSV and downloadable CSV URLs from the table and query pages.

The links use ?_size=max and so by default will return 1,000 rows.

Also fixes #303 - table names ending in .json or .csv are now detected and
URLs are generated that look like this instead:

	/test_tables/table%2Fwith%2Fslashes.csv?_format=csv

The ?_format= option is available for everything else too, but we link to the
.csv / .json versions in most cases because they are aesthetically pleasing.

tests/test_api.py

@@ -507,7 +507,7 @@ def test_table_shape_object_compound_primary_Key(app_client):
 
 
 def test_table_with_slashes_in_name(app_client):
-    response = app_client.get('/test_tables/table%2Fwith%2Fslashes.csv.json?_shape=objects')
+    response = app_client.get('/test_tables/table%2Fwith%2Fslashes.csv?_shape=objects&_format=json')
     assert response.status == 200
     data = response.json
     assert data['rows'] == [{

tests/test_csv.py

@@ -0,0 +1,37 @@
+from .fixtures import app_client # noqa
+
+EXPECTED_TABLE_CSV = '''id,content
+1,hello
+2,world
+3,
+'''.replace('\n', '\r\n')
+
+EXPECTED_CUSTOM_CSV = '''content
+hello
+world
+""
+'''.replace('\n', '\r\n')
+
+
+def test_table_csv(app_client):
+    response = app_client.get('/test_tables/simple_primary_key.csv')
+    assert response.status == 200
+    assert 'text/plain; charset=utf-8' == response.headers['Content-Type']
+    assert EXPECTED_TABLE_CSV == response.text
+
+
+def test_custom_sql_csv(app_client):
+    response = app_client.get(
+        '/test_tables.csv?sql=select+content+from+simple_primary_key'
+    )
+    assert response.status == 200
+    assert 'text/plain; charset=utf-8' == response.headers['Content-Type']
+    assert EXPECTED_CUSTOM_CSV == response.text
+
+
+def test_table_csv_download(app_client):
+    response = app_client.get('/test_tables/simple_primary_key.csv?_dl=1')
+    assert response.status == 200
+    assert 'text/csv; charset=utf-8' == response.headers['Content-Type']
+    expected_disposition = 'attachment; filename="simple_primary_key.csv"'
+    assert expected_disposition == response.headers['Content-Disposition']

tests/test_html.py

@@ -274,6 +274,21 @@ def test_table_html_simple_primary_key(app_client):
     ] == [[str(td) for td in tr.select('td')] for tr in table.select('tbody tr')]
 
 
+def test_table_csv_json_export_links(app_client):
+    response = app_client.get('/test_tables/simple_primary_key')
+    assert response.status == 200
+    links = Soup(response.body, "html.parser").find("p", {
+        "class": "export-links"
+    }).findAll("a")
+    actual = [l["href"].split("/")[-1] for l in links]
+    expected = [
+        "simple_primary_key.json",
+        "simple_primary_key.csv?_size=max",
+        "simple_primary_key.csv?_dl=1&_size=max"
+    ]
+    assert expected == actual
+
+
 def test_row_html_simple_primary_key(app_client):
     response = app_client.get('/test_tables/simple_primary_key/1')
     assert response.status == 200

tests/test_utils.py

@@ -299,3 +299,54 @@ def test_compound_keys_after_sql():
   or
 (a = :p0 and b = :p1 and c > :p2))
     '''.strip() == utils.compound_keys_after_sql(['a', 'b', 'c'])
+
+
+def table_exists(table):
+    return table == "exists.csv"
+
+
+@pytest.mark.parametrize(
+    "table_and_format,expected_table,expected_format",
+    [
+        ("blah", "blah", None),
+        ("blah.csv", "blah", "csv"),
+        ("blah.json", "blah", "json"),
+        ("blah.baz", "blah.baz", None),
+        ("exists.csv", "exists.csv", None),
+    ],
+)
+def test_resolve_table_and_format(
+    table_and_format, expected_table, expected_format
+):
+    actual_table, actual_format = utils.resolve_table_and_format(
+        table_and_format, table_exists
+    )
+    assert expected_table == actual_table
+    assert expected_format == actual_format
+
+
+@pytest.mark.parametrize(
+    "path,format,extra_qs,expected",
+    [
+        ("/foo?sql=select+1", "csv", {}, "/foo.csv?sql=select+1"),
+        ("/foo?sql=select+1", "json", {}, "/foo.json?sql=select+1"),
+        ("/foo/bar", "json", {}, "/foo/bar.json"),
+        ("/foo/bar", "csv", {}, "/foo/bar.csv"),
+        ("/foo/bar.csv", "json", {}, "/foo/bar.csv?_format=json"),
+        ("/foo/bar", "csv", {"_dl": 1}, "/foo/bar.csv?_dl=1"),
+        ("/foo/b.csv", "json", {"_dl": 1}, "/foo/b.csv?_dl=1&_format=json"),
+        (
+            "/sf-trees/Street_Tree_List?_search=cherry&_size=1000",
+            "csv",
+            {"_dl": 1},
+            "/sf-trees/Street_Tree_List.csv?_search=cherry&_size=1000&_dl=1",
+        ),
+    ],
+)
+def test_path_with_format(path, format, extra_qs, expected):
+    request = Request(
+        path.encode('utf8'),
+        {}, '1.1', 'GET', None
+    )
+    actual = utils.path_with_format(request, format, extra_qs)
+    assert expected == actual