From 8d8decf114aebf10188cfdf52a8479cd24d1e3e5 Mon Sep 17 00:00:00 2001
From: Julien BLACHE <jb@jblache.org>
Date: Sat, 2 May 2009 20:40:11 +0200
Subject: [PATCH 1/2] Add a variant of evhttp_send_reply_chunk() with a
 callback on evhttp_write_buffer()

evhttp_write_buffer() used by evhttp_send_reply_chunk() can take callback
executed when (part of) the buffer has been written. Using this callback to
schedule the next chunk avoids buffering large amounts of data in memory.
---
 http.c                | 10 ++++++++--
 include/event2/http.h | 18 ++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/http.c b/http.c
index e8672b77..33541728 100644
--- a/http.c
+++ b/http.c
@@ -2658,7 +2658,8 @@ evhttp_send_reply_start(struct evhttp_request *req, int code,
 }
 
 void
-evhttp_send_reply_chunk(struct evhttp_request *req, struct evbuffer *databuf)
+evhttp_send_reply_chunk_with_cb(struct evhttp_request *req, struct evbuffer *databuf,
+    void (*cb)(struct evhttp_connection *, void *), void *arg)
 {
 	struct evhttp_connection *evcon = req->evcon;
 	struct evbuffer *output;
@@ -2680,9 +2681,14 @@ evhttp_send_reply_chunk(struct evhttp_request *req, struct evbuffer *databuf)
 	if (req->chunked) {
 		evbuffer_add(output, "\r\n", 2);
 	}
-	evhttp_write_buffer(evcon, NULL, NULL);
+	evhttp_write_buffer(evcon, cb, arg);
 }
 
+void
+evhttp_send_reply_chunk(struct evhttp_request *req, struct evbuffer *databuf)
+{
+	evhttp_send_reply_chunk_with_cb(req, databuf, NULL, NULL);
+}
 void
 evhttp_send_reply_end(struct evhttp_request *req)
 {
diff --git a/include/event2/http.h b/include/event2/http.h
index 956d9d6c..466a5a86 100644
--- a/include/event2/http.h
+++ b/include/event2/http.h
@@ -38,6 +38,7 @@ extern "C" {
 struct evbuffer;
 struct event_base;
 struct bufferevent;
+struct evhttp_connection;
 
 /** @file event2/http.h
  *
@@ -407,6 +408,23 @@ void evhttp_send_reply_start(struct evhttp_request *req, int code,
 */
 void evhttp_send_reply_chunk(struct evhttp_request *req,
     struct evbuffer *databuf);
+
+/**
+   Send another data chunk as part of an ongoing chunked reply.
+
+   The reply chunk consists of the data in databuf.  After calling
+   evhttp_send_reply_chunk() databuf will be empty, but the buffer is
+   still owned by the caller and needs to be deallocated by the caller
+   if necessary.
+
+   @param req a request object
+   @param databuf the data chunk to send as part of the reply.
+   @param cb callback funcion
+   @param call back's argument.
+*/
+void evhttp_send_reply_chunk_with_cb(struct evhttp_request *, struct evbuffer *,
+    void (*cb)(struct evhttp_connection *, void *), void *arg);
+
 /**
    Complete a chunked reply, freeing the request as appropriate.
 

From b0bd7fe1db93a1adde29587e12ed78726f962012 Mon Sep 17 00:00:00 2001
From: Balint Reczey <balint@balintreczey.hu>
Date: Mon, 18 Nov 2013 16:06:16 +0100
Subject: [PATCH 2/2] Allow registering callback for parsing HTTP headers
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Slightly changed version of Espen Jürgensen's
commit 548141e72312126fa6121f6a5f436đ251c7fb1251 for forked-daapd.
---
 http.c                       | 15 +++++++++++++++
 include/event2/http.h        |  9 +++++++++
 include/event2/http_struct.h |  8 ++++++++
 3 files changed, 32 insertions(+)

diff --git a/http.c b/http.c
index 33541728..826deffe 100644
--- a/http.c
+++ b/http.c
@@ -2150,6 +2150,14 @@ evhttp_read_header(struct evhttp_connection *evcon,
 	/* Disable reading for now */
 	bufferevent_disable(evcon->bufev, EV_READ);
 
+	/* Callback can shut down connection with negative return value */
+	if (req->header_cb != NULL) {
+		if ((*req->header_cb)(req, req->cb_arg) < 0) {
+			evhttp_connection_fail_(evcon, EVREQ_HTTP_EOF);
+			return;
+		}
+	}
+
 	/* Done reading headers, do the real work */
 	switch (req->kind) {
 	case EVHTTP_REQUEST:
@@ -3818,6 +3826,13 @@ evhttp_request_set_chunked_cb(struct evhttp_request *req,
 	req->chunk_cb = cb;
 }
 
+void
+evhttp_request_set_header_cb(struct evhttp_request *req,
+    int (*cb)(struct evhttp_request *, void *))
+{
+	req->header_cb = cb;
+}
+
 void
 evhttp_request_set_error_cb(struct evhttp_request *req,
     void (*cb)(enum evhttp_request_error, void *))
diff --git a/include/event2/http.h b/include/event2/http.h
index 466a5a86..068120c7 100644
--- a/include/event2/http.h
+++ b/include/event2/http.h
@@ -504,6 +504,15 @@ struct evhttp_request *evhttp_request_new(
 void evhttp_request_set_chunked_cb(struct evhttp_request *,
     void (*cb)(struct evhttp_request *, void *));
 
+/**
+ * Register callback for additional parsing of request headers.
+ * @param cb will be called after receiving and parsing the full header.
+ * It allows analyzing the header and possibly closing the connection
+ * by returning a value < 0.
+ */
+void evhttp_request_set_header_cb(struct evhttp_request *,
+    int (*cb)(struct evhttp_request *, void *));
+
 /**
  * The different error types supported by evhttp
  *
diff --git a/include/event2/http_struct.h b/include/event2/http_struct.h
index 25e19bd9..4ca196ee 100644
--- a/include/event2/http_struct.h
+++ b/include/event2/http_struct.h
@@ -120,6 +120,14 @@ struct {
 	 * the regular callback.
 	 */
 	void (*chunk_cb)(struct evhttp_request *, void *);
+
+	/*
+	 * Callback added for forked-daapd so they can collect ICY
+	 * (shoutcast) metadata from the http header. If return
+	 * int is negative the connection will be closed.
+	 */
+	int (*header_cb)(struct evhttp_request *, void *);
+
 	/*
 	 * Error callback - called when error is occured.
 	 * @see evhttp_request_error for error types.