[FFmpeg-devel] [PATCH 1/5] Early version of IPFS protocol support.

[Mark Gaiser <markg85@gmail.com>]

Signed-off-by: Mark Gaiser <markg85@gmail.com>
---
 configure               |   1 +
 doc/protocols.texi      |  30 ++++++
 libavformat/Makefile    |   1 +
 libavformat/ipfs.c      | 202 ++++++++++++++++++++++++++++++++++++++++
 libavformat/protocols.c |   2 +
 5 files changed, 236 insertions(+)
 create mode 100644 libavformat/ipfs.c

diff --git a/configure b/configure
index 5b19a35f59..e466f924a3 100755
--- a/configure
+++ b/configure
@@ -3585,6 +3585,7 @@ udp_protocol_select="network"
 udplite_protocol_select="network"
 unix_protocol_deps="sys_un_h"
 unix_protocol_select="network"
+ipfs_protocol_select="https_protocol"
 
 # external library protocols
 libamqp_protocol_deps="librabbitmq"
diff --git a/doc/protocols.texi b/doc/protocols.texi
index d207df0b52..7c9c0a4808 100644
--- a/doc/protocols.texi
+++ b/doc/protocols.texi
@@ -2025,5 +2025,35 @@ decoding errors.
 
 @end table
 
+@section ipfs
+
+InterPlanetary File System (IPFS) protocol support. One can access files stored 
+on the IPFS network through so called gateways. Those are http(s) endpoints.
+This protocol wraps the IPFS native protocols (ipfs:// and ipns://) to be send 
+to such a gateway. Users can (and should) host their own node which means this 
+protocol will use your local machine gateway to access files on the IPFS network.
+
+If a user doesn't have a node of their own then the public gateway dweb.link is 
+used by default.
+
+You can use this protocol in 2 ways. Using IPFS:
+@example
+ffplay ipfs://QmbGtJg23skhvFmu9mJiePVByhfzu5rwo74MEkVDYAmF5T
+@end example
+
+Or the IPNS protocol (IPNS is mutable IPFS):
+@example
+ffplay ipns://QmbGtJg23skhvFmu9mJiePVByhfzu5rwo74MEkVDYAmF5T
+@end example
+
+You can also change the gateway to be used:
+
+@table @option
+
+@item gateway
+Defines the gateway to use. When nothing is provided the protocol will first try 
+your local gateway. If that fails dweb.link will be used.
+
+@end table
 
 @c man end PROTOCOLS
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 3dc6a479cc..983a77f4f2 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -656,6 +656,7 @@ OBJS-$(CONFIG_SRTP_PROTOCOL)             += srtpproto.o srtp.o
 OBJS-$(CONFIG_SUBFILE_PROTOCOL)          += subfile.o
 OBJS-$(CONFIG_TEE_PROTOCOL)              += teeproto.o tee_common.o
 OBJS-$(CONFIG_TCP_PROTOCOL)              += tcp.o
+OBJS-$(CONFIG_IPFS_PROTOCOL)             += ipfs.o
 TLS-OBJS-$(CONFIG_GNUTLS)                += tls_gnutls.o
 TLS-OBJS-$(CONFIG_LIBTLS)                += tls_libtls.o
 TLS-OBJS-$(CONFIG_MBEDTLS)               += tls_mbedtls.o
diff --git a/libavformat/ipfs.c b/libavformat/ipfs.c
new file mode 100644
index 0000000000..4cc65750ed
--- /dev/null
+++ b/libavformat/ipfs.c
@@ -0,0 +1,202 @@
+/*
+ * IPFS protocol.
+ * Copyright (c) 2021 Mark Gaiser
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
+#include "libavutil/internal.h"
+#include "libavutil/opt.h"
+#include "libavutil/tree.h"
+#include "avformat.h"
+#include <fcntl.h>
+#if HAVE_IO_H
+#include <io.h>
+#endif
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <sys/stat.h>
+#include <stdlib.h>
+#include "os_support.h"
+#include "url.h"
+
+typedef struct Context {
+    AVClass *class;
+    URLContext *inner;
+    char *fulluri;
+    char *gateway;
+} Context;
+
+static int ipfs_open(URLContext *h, const char *uri, int flags, AVDictionary **options)
+{
+    const char *gatewaysuffix;
+    int ret = 0;
+    Context *c = h->priv_data;
+    
+    if (!av_strstart(uri, "ipfs://", &gatewaysuffix) &&
+        !av_strstart(uri, "ipfs:", &gatewaysuffix)) {
+        av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri);
+        ret = AVERROR(EINVAL);
+        goto err;
+    }
+    
+    char* ipfs_gateway = "https://ipfs.io/ipfs/";
+    
+    c->fulluri = malloc(strlen(ipfs_gateway)+strlen(gatewaysuffix) + 1);
+    
+    strcpy(c->fulluri, ipfs_gateway);
+    strcat(c->fulluri, gatewaysuffix);
+    
+    if ((ret = ffurl_open_whitelist(&c->inner, c->fulluri, flags,
+                                    &h->interrupt_callback, options,
+                                    h->protocol_whitelist, h->protocol_blacklist, h)) < 0) {
+        av_log(h, AV_LOG_ERROR, "Unable to open resource: %s\n", c->fulluri);
+        goto err;
+    }
+    
+err:
+    return ret;
+}
+
+static int ipfs_read(URLContext *h, unsigned char *buf, int size)
+{
+    Context *c = h->priv_data;
+    int ret;
+
+    ret = ffurl_read(c->inner, buf, size);
+
+    return ret;
+}
+
+static int64_t ipfs_seek(URLContext *h, int64_t pos, int whence)
+{
+    Context *c = h->priv_data;
+    int64_t ret;
+
+    ret = ffurl_seek(c->inner, pos, whence);
+
+    return ret;
+}
+
+static int ipfs_close(URLContext *h)
+{
+    Context *c = h->priv_data;
+    int ret;
+
+    ret = ffurl_closep(&c->inner);
+
+    return ret;
+}
+
+static int ipns_open(URLContext *h, const char *uri, int flags, AVDictionary **options)
+{
+    const char *gatewaysuffix;
+    int ret = 0;
+    Context *c = h->priv_data;
+    
+    if (!av_strstart(uri, "ipns://", &gatewaysuffix) &&
+        !av_strstart(uri, "ipns:", &gatewaysuffix)) {
+        av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri);
+        ret = AVERROR(EINVAL);
+        goto err;
+    }
+    
+    char* ipfs_gateway = "https://ipfs.io/ipns/";
+    
+    c->fulluri = malloc(strlen(ipfs_gateway)+strlen(gatewaysuffix) + 1);
+    
+    strcpy(c->fulluri, ipfs_gateway);
+    strcat(c->fulluri, gatewaysuffix);
+    
+    if ((ret = ffurl_open_whitelist(&c->inner, c->fulluri, flags,
+                                    &h->interrupt_callback, options,
+                                    h->protocol_whitelist, h->protocol_blacklist, h)) < 0) {
+        av_log(h, AV_LOG_ERROR, "Unable to open resource: %s\n", c->fulluri);
+        goto err;
+    }
+    
+err:
+    return ret;
+}
+
+static int ipns_read(URLContext *h, unsigned char *buf, int size)
+{
+    Context *c = h->priv_data;
+    int ret;
+
+    ret = ffurl_read(c->inner, buf, size);
+
+    return ret;
+}
+
+static int64_t ipns_seek(URLContext *h, int64_t pos, int whence)
+{
+    Context *c = h->priv_data;
+    int64_t ret;
+
+    ret = ffurl_seek(c->inner, pos, whence);
+
+    return ret;
+}
+
+static int ipns_close(URLContext *h)
+{
+    Context *c = h->priv_data;
+    int ret;
+
+    ret = ffurl_closep(&c->inner);
+
+    return ret;
+}
+
+#define OFFSET(x) offsetof(Context, x)
+#define D AV_OPT_FLAG_DECODING_PARAM
+
+static const AVOption options[] = {
+    {"gateway", "The gateway to ask for IPFS data.", OFFSET(gateway), AV_OPT_TYPE_BINARY, .flags = D },
+    {NULL},
+};
+
+static const AVClass ipfs_context_class = {
+    .class_name = "IPFS",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+const URLProtocol ff_ipfs_protocol = {
+    .name                = "ipfs",
+    .url_open2           = ipfs_open,
+    .url_read            = ipfs_read,
+    .url_seek            = ipfs_seek,
+    .url_close           = ipfs_close,
+    .priv_data_size      = sizeof(Context),
+    .priv_data_class     = &ipfs_context_class,
+};
+
+const URLProtocol ff_infs_protocol = {
+    .name                = "ipns",
+    .url_open2           = ipfs_open,
+    .url_read            = ipfs_read,
+    .url_seek            = ipfs_seek,
+    .url_close           = ipfs_close,
+    .priv_data_size      = sizeof(Context),
+    .priv_data_class     = &ipfs_context_class,
+};
diff --git a/libavformat/protocols.c b/libavformat/protocols.c
index 948fae411f..675b684bd3 100644
--- a/libavformat/protocols.c
+++ b/libavformat/protocols.c
@@ -73,6 +73,8 @@ extern const URLProtocol ff_libsrt_protocol;
 extern const URLProtocol ff_libssh_protocol;
 extern const URLProtocol ff_libsmbclient_protocol;
 extern const URLProtocol ff_libzmq_protocol;
+extern const URLProtocol ff_ipfs_protocol;
+extern const URLProtocol ff_ipns_protocol;
 
 #include "libavformat/protocol_list.c"
 
-- 
2.35.1

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