From 2c0aca4887ed65167606a5fd084f35d046e2a00a Mon Sep 17 00:00:00 2001
From: Simon Willison <swillison@gmail.com>
Date: Thu, 10 Dec 2020 15:28:44 -0800
Subject: [PATCH] _header=off option for CSV export, closes #1133

---
 datasette/views/base.py |  3 ++-
 docs/csv_export.rst     | 16 ++++++++++++++++
 tests/test_csv.py       |  8 ++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/datasette/views/base.py b/datasette/views/base.py
index b8860b74..76e03206 100644
--- a/datasette/views/base.py
+++ b/datasette/views/base.py
@@ -307,7 +307,8 @@ class DataView(BaseView):
                     if not first:
                         data, _, _ = await self.data(request, database, hash, **kwargs)
                     if first:
-                        await writer.writerow(headings)
+                        if request.args.get("_header") != "off":
+                            await writer.writerow(headings)
                         first = False
                     next = data.get("next")
                     for row in data["rows"]:
diff --git a/docs/csv_export.rst b/docs/csv_export.rst
index 0bda20ef..7f0d8396 100644
--- a/docs/csv_export.rst
+++ b/docs/csv_export.rst
@@ -28,6 +28,22 @@ file, which looks like this and has the following options:
 
 You can try that out on https://latest.datasette.io/fixtures/facetable?_size=4
 
+.. _csv_export_url_parameters:
+
+URL parameters
+--------------
+
+The following options can be used to customize the CSVs returned by Datasette.
+
+``?_header=off``
+    This removes the first row of the CSV file specifying the headings - only the row data will be returned.
+
+``?_stream=on``
+    Stream all matching records, not just the first page of results. See below.
+
+``?_dl=on``
+    Causes Datasette to return a ``content-disposition: attachment; filename="filename.csv"`` header.
+
 Streaming all records
 ---------------------
 
diff --git a/tests/test_csv.py b/tests/test_csv.py
index 0fd665a9..6b17033c 100644
--- a/tests/test_csv.py
+++ b/tests/test_csv.py
@@ -64,6 +64,14 @@ def test_table_csv_cors_headers(app_client_with_cors):
     assert "*" == response.headers["Access-Control-Allow-Origin"]
 
 
+def test_table_csv_no_header(app_client):
+    response = app_client.get("/fixtures/simple_primary_key.csv?_header=off")
+    assert response.status == 200
+    assert not response.headers.get("Access-Control-Allow-Origin")
+    assert "text/plain; charset=utf-8" == response.headers["content-type"]
+    assert EXPECTED_TABLE_CSV.split("\r\n", 1)[1] == response.text
+
+
 def test_table_csv_with_labels(app_client):
     response = app_client.get("/fixtures/facetable.csv?_labels=1")
     assert response.status == 200