feat: support net.http_delete with request body

Addresses #77 (comment).
Now it's possible to do:

```sql
select net.http_delete(
    url  :='http://localhost:8080/delete_w_body'
,   body := '{"key": "val"}'
);
```

Backwards compatibility is tested. No body will be sent if
the body parameter is NULL (the default).

nix/nginx/conf/custom.conf

@@ -49,6 +49,15 @@ location /delete {
   echo_duplicate 1 $echo_client_request_headers$is_args$query_string;
 }
 
+location /delete_w_body {
+  if ($request_method != 'DELETE'){
+      return 405;
+  }
+
+  echo_read_request_body;
+  echo $request_body;
+}
+
 location /redirect_me {
   return 301 /to_here;
 }

sql/pg_net--0.14.0--0.15.0.sql

@@ -0,0 +1,43 @@
+drop function net.http_delete (text, jsonb, jsonb, integer);
+
+create function net.http_delete(
+    -- url for the request
+    url text,
+    -- key/value pairs to be url encoded and appended to the `url`
+    params jsonb default '{}'::jsonb,
+    -- key/values to be included in request headers
+    headers jsonb default '{}'::jsonb,
+    -- the maximum number of milliseconds the request may take before being cancelled
+    timeout_milliseconds int default 5000,
+    -- optional body of the request
+    body jsonb default NULL
+)
+    -- request_id reference
+    returns bigint
+    volatile
+    parallel safe
+    language plpgsql
+as $$
+declare
+    request_id bigint;
+    params_array text[];
+begin
+    select coalesce(array_agg(net._urlencode_string(key) || '=' || net._urlencode_string(value)), '{}')
+    into params_array
+    from jsonb_each_text(params);
+
+    -- Add to the request queue
+    insert into net.http_request_queue(method, url, headers, body, timeout_milliseconds)
+    values (
+        'DELETE',
+        net._encode_url_with_params_array(url, params_array),
+        headers,
+        convert_to(body::text, 'UTF8'),
+        timeout_milliseconds
+    )
+    returning id
+    into request_id;
+
+    return request_id;
+end
+$$;

sql/pg_net.sql

@@ -223,11 +223,12 @@ create or replace function net.http_delete(
     -- key/values to be included in request headers
     headers jsonb default '{}'::jsonb,
     -- the maximum number of milliseconds the request may take before being cancelled
-    timeout_milliseconds int default 5000
+    timeout_milliseconds int default 5000,
+    -- optional body of the request
+    body jsonb default NULL
 )
     -- request_id reference
     returns bigint
-    strict
     volatile
     parallel safe
     language plpgsql
@@ -241,11 +242,12 @@ begin
     from jsonb_each_text(params);
 
     -- Add to the request queue
-    insert into net.http_request_queue(method, url, headers, timeout_milliseconds)
+    insert into net.http_request_queue(method, url, headers, body, timeout_milliseconds)
     values (
         'DELETE',
         net._encode_url_with_params_array(url, params_array),
         headers,
+        convert_to(body::text, 'UTF8'),
         timeout_milliseconds
     )
     returning id

src/core.c

@@ -124,6 +124,9 @@ static void init_curl_handle(CURLM *curl_mhandle, MemoryContext curl_memctx, int
 
   if (strcasecmp(method, "DELETE") == 0) {
     EREPORT_CURL_SETOPT(curl_ez_handle, CURLOPT_CUSTOMREQUEST, "DELETE");
+    if (reqBody) {
+      EREPORT_CURL_SETOPT(curl_ez_handle, CURLOPT_POSTFIELDS, reqBody);
+    }
   }
 
   EREPORT_CURL_SETOPT(curl_ez_handle, CURLOPT_WRITEFUNCTION, body_cb);

test/test_http_delete.py

@@ -160,3 +160,35 @@ def test_http_delete_positional_args(sess):
     assert response is not None
     assert response[0] == "SUCCESS"
     assert response[1] == "ok"
+
+
+def test_http_delete_with_body(sess):
+    """delete with request body works"""
+
+    # Create a request
+    (request_id,) = sess.execute(text(
+        """
+        select net.http_delete(
+            url  :='http://localhost:8080/delete_w_body'
+        ,   body := '{"key": "val"}'
+        );
+    """
+    )).fetchone()
+
+    # Commit so background worker can start
+    sess.commit()
+
+    # Collect the response, waiting as needed
+    (response_json,) = sess.execute(
+        text(
+            """
+        select
+            ((x.response).body)::jsonb body_json
+        from
+            net._http_collect_response(:request_id, async:=false) x;
+    """
+        ),
+        {"request_id": request_id},
+        ).fetchone()
+
+    assert response_json["key"] == "val"