datasette.urls.table(..., format="json"), closes #1035

Also improved tests for datasette.urls and added format= to some other methods

datasette/app.py

@@ -53,6 +53,7 @@ from .utils import (
     format_bytes,
     module_from_path,
     parse_metadata,
+    path_with_format,
     resolve_env_secrets,
     sqlite3,
     to_css_class,
@@ -1285,13 +1286,16 @@ class Urls:
     def __init__(self, ds):
         self.ds = ds
 
-    def path(self, path):
+    def path(self, path, format=None):
         if path.startswith("/"):
             path = path[1:]
-        return self.ds.config("base_url") + path
+        path = self.ds.config("base_url") + path
+        if format is not None:
+            path = path_with_format(path=path, format=format)
+        return path
 
-    def instance(self):
-        return self.path("")
+    def instance(self, format=None):
+        return self.path("", format=format)
 
     def static(self, path):
         return self.path("-/static/{}".format(path))
@@ -1302,21 +1306,33 @@ class Urls:
     def logout(self):
         return self.path("-/logout")
 
-    def database(self, database):
+    def database(self, database, format=None):
         db = self.ds.databases[database]
         if self.ds.config("hash_urls") and db.hash:
-            return self.path("{}-{}".format(database, db.hash[:HASH_LENGTH]))
+            path = self.path(
+                "{}-{}".format(database, db.hash[:HASH_LENGTH]), format=format
+            )
         else:
-            return self.path(database)
+            path = self.path(database, format=format)
+        return path
 
-    def table(self, database, table):
-        return "{}/{}".format(self.database(database), urllib.parse.quote_plus(table))
+    def table(self, database, table, format=None):
+        path = "{}/{}".format(self.database(database), urllib.parse.quote_plus(table))
+        if format is not None:
+            path = path_with_format(path=path, format=format)
+        return path
 
-    def query(self, database, query):
-        return "{}/{}".format(self.database(database), urllib.parse.quote_plus(query))
+    def query(self, database, query, format=None):
+        path = "{}/{}".format(self.database(database), urllib.parse.quote_plus(query))
+        if format is not None:
+            path = path_with_format(path=path, format=format)
+        return path
 
-    def row(self, database, table, row_path):
-        return "{}/{}".format(self.table(database, table), row_path)
+    def row(self, database, table, row_path, format=None):
+        path = "{}/{}".format(self.table(database, table), row_path)
+        if format is not None:
+            path = path_with_format(path=path, format=format)
+        return path
 
     def row_blob(self, database, table, row_path, column):
         return self.table(database, table) + "/{}.blob?_blob_column={}".format(

datasette/utils/__init__.py

@@ -678,9 +678,11 @@ async def resolve_table_and_format(
     return table_and_format, None
 
 
-def path_with_format(request, format, extra_qs=None, replace_format=None):
+def path_with_format(
+    *, request=None, path=None, format=None, extra_qs=None, replace_format=None
+):
     qs = extra_qs or {}
-    path = request.path
+    path = request.path if request else path
     if replace_format and path.endswith(".{}".format(replace_format)):
         path = path[: -(1 + len(replace_format))]
     if "." in path:
@@ -689,11 +691,11 @@ def path_with_format(request, format, extra_qs=None, replace_format=None):
         path = "{}.{}".format(path, format)
     if qs:
         extra = urllib.parse.urlencode(sorted(qs.items()))
-        if request.query_string:
+        if request and request.query_string:
             path = "{}?{}&{}".format(path, request.query_string, extra)
         else:
             path = "{}?{}".format(path, extra)
-    elif request.query_string:
+    elif request and request.query_string:
         path = "{}?{}".format(path, request.query_string)
     return path
 

datasette/views/base.py

@@ -333,8 +333,8 @@ class DataView(BaseView):
                                         cell = self.ds.absolute_url(
                                             request,
                                             path_with_format(
-                                                request,
-                                                "blob",
+                                                request=request,
+                                                format="blob",
                                                 extra_qs={
                                                     "_blob_column": column,
                                                     "_blob_hash": hashlib.sha256(
@@ -535,11 +535,13 @@ class DataView(BaseView):
                 it_can_render = await await_me_maybe(it_can_render)
                 if it_can_render:
                     renderers[key] = path_with_format(
-                        request, key, {**url_labels_extra}
+                        request=request, format=key, extra_qs={**url_labels_extra}
                     )
 
             url_csv_args = {"_size": "max", **url_labels_extra}
-            url_csv = path_with_format(request, "csv", url_csv_args)
+            url_csv = path_with_format(
+                request=request, format="csv", extra_qs=url_csv_args
+            )
             url_csv_path = url_csv.split("?")[0]
             context = {
                 **data,

datasette/views/database.py

@@ -346,8 +346,8 @@ class QueryView(DataView):
                             )
                         elif isinstance(display_value, bytes):
                             blob_url = path_with_format(
-                                request,
-                                "blob",
+                                request=request,
+                                format="blob",
                                 extra_qs={
                                     "_blob_column": column,
                                     "_blob_hash": hashlib.sha256(

docs/internals.rst

@@ -396,10 +396,10 @@ datasette.urls
 
 The ``datasette.urls`` object contains methods for building URLs to pages within Datasette. Plugins should use this to link to pages, since these methods take into account any :ref:`config_base_url` configuration setting that might be in effect.
 
-``datasette.urls.instance()``
-    Returns the URL to the Datasette instance root page. This is usually ``"/"``
+``datasette.urls.instance(format=None)``
+    Returns the URL to the Datasette instance root page. This is usually ``"/"``.
 
-``datasette.urls.path(path)``
+``datasette.urls.path(path, format=None)``
     Takes a path and returns the full path, taking ``base_url`` into account.
 
     For example, ``datasette.urls.path("-/logout")`` will return the path to the logout page, which will be ``"/-/logout"`` by default or ``/prefix-path/-/logout`` if ``base_url`` is set to ``/prefix-path/``
@@ -423,13 +423,13 @@ The ``datasette.urls`` object contains methods for building URLs to pages within
 
     ``datasette.url.static_plugins("datasette_cluster_map", "datasette-cluster-map.js")`` would return ``"/-/static-plugins/datasette_cluster_map/datasette-cluster-map.js"``
 
-``datasette.urls.database(database_name)``
+``datasette.urls.database(database_name, format=None)``
     Returns the URL to a database page, for example ``"/fixtures"``
 
-``datasette.urls.table(database_name, table_name)``
+``datasette.urls.table(database_name, table_name, format=None)``
     Returns the URL to a table page, for example ``"/fixtures/facetable"``
 
-``datasette.urls.query(database_name, query_name)``
+``datasette.urls.query(database_name, query_name, format=None)``
     Returns the URL to a query page, for example ``"/fixtures/pragma_cache_size"``
 
 These functions can be accessed via the ``{{ urls }}`` object in Datasette templates, for example:
@@ -441,6 +441,8 @@ These functions can be accessed via the ``{{ urls }}`` object in Datasette templ
     <a href="{{ urls.table("fixtures", "facetable") }}">facetable table</a>
     <a href="{{ urls.query("fixtures", "pragma_cache_size") }}">pragma_cache_size query</a>
 
+Use the ``format="json"`` (or ``"csv"`` or other formats supported by plugins) arguments to get back URLs to the JSON representation. This is usually the path with ``.json`` added on the end, but it may use ``?_format=json`` in cases where the path already includes ``.json``, for example a URL to a table named ``table.json``.
+
 .. _internals_database:
 
 Database class

tests/test_internals_urls.py

@@ -82,18 +82,44 @@ def test_logout(ds, base_url, expected):
 
 
 @pytest.mark.parametrize(
-    "base_url,expected",
+    "base_url,format,expected",
     [
-        ("/", "/:memory:"),
-        ("/prefix/", "/prefix/:memory:"),
+        ("/", None, "/:memory:"),
+        ("/prefix/", None, "/prefix/:memory:"),
+        ("/", "json", "/:memory:.json"),
     ],
 )
-def test_database(ds, base_url, expected):
+def test_database(ds, base_url, format, expected):
     ds._config["base_url"] = base_url
-    assert ds.urls.database(":memory:") == expected
-    # Do table and query while we are here
-    assert ds.urls.table(":memory:", "name") == expected + "/name"
-    assert ds.urls.query(":memory:", "name") == expected + "/name"
+    assert ds.urls.database(":memory:", format=format) == expected
+
+
+@pytest.mark.parametrize(
+    "base_url,name,format,expected",
+    [
+        ("/", "name", None, "/:memory:/name"),
+        ("/prefix/", "name", None, "/prefix/:memory:/name"),
+        ("/", "name", "json", "/:memory:/name.json"),
+        ("/", "name.json", "json", "/:memory:/name.json?_format=json"),
+    ],
+)
+def test_table_and_query(ds, base_url, name, format, expected):
+    ds._config["base_url"] = base_url
+    assert ds.urls.table(":memory:", name, format=format) == expected
+    assert ds.urls.query(":memory:", name, format=format) == expected
+
+
+@pytest.mark.parametrize(
+    "base_url,format,expected",
+    [
+        ("/", None, "/:memory:/facetable/1"),
+        ("/prefix/", None, "/prefix/:memory:/facetable/1"),
+        ("/", "json", "/:memory:/facetable/1.json"),
+    ],
+)
+def test_row(ds, base_url, format, expected):
+    ds._config["base_url"] = base_url
+    assert ds.urls.row(":memory:", "facetable", "1", format=format) == expected
 
 
 @pytest.mark.parametrize("base_url", ["/", "/prefix/"])

tests/test_utils.py

@@ -382,15 +382,19 @@ def test_table_columns():
 )
 def test_path_with_format(path, format, extra_qs, expected):
     request = Request.fake(path)
-    actual = utils.path_with_format(request, format, extra_qs)
+    actual = utils.path_with_format(request=request, format=format, extra_qs=extra_qs)
     assert expected == actual
 
 
 def test_path_with_format_replace_format():
     request = Request.fake("/foo/bar.csv")
-    assert utils.path_with_format(request, "blob") == "/foo/bar.csv?_format=blob"
     assert (
-        utils.path_with_format(request, "blob", replace_format="csv") == "/foo/bar.blob"
+        utils.path_with_format(request=request, format="blob")
+        == "/foo/bar.csv?_format=blob"
+    )
+    assert (
+        utils.path_with_format(request=request, format="blob", replace_format="csv")
+        == "/foo/bar.blob"
     )