[FFmpeg-devel] [PATCH v11 1/1] avformat: Add IPFS protocol support.
Michael Niedermayer
michael at niedermayer.cc
Fri Apr 1 18:39:06 EEST 2022
On Fri, Apr 01, 2022 at 02:23:23AM +0200, Mark Gaiser wrote:
> On Fri, Apr 1, 2022 at 2:09 AM Mark Gaiser <markg85 at gmail.com> wrote:
>
> > This patch adds support for:
> > - ffplay ipfs://<cid>
> > - ffplay ipns://<cid>
> >
> > IPFS data can be played from so called "ipfs gateways".
> > A gateway is essentially a webserver that gives access to the
> > distributed IPFS network.
> >
> > This protocol support (ipfs and ipns) therefore translates
> > ipfs:// and ipns:// to a http:// url. This resulting url is
> > then handled by the http protocol. It could also be https
> > depending on the gateway provided.
> >
> > To use this protocol, a gateway must be provided.
> > If you do nothing it will try to find it in your
> > $HOME/.ipfs/gateway file. The ways to set it manually are:
> > 1. Define a -gateway <url> to the gateway.
> > 2. Define $IPFS_GATEWAY with the full http link to the gateway.
> > 3. Define $IPFS_PATH and point it to the IPFS data path.
> > 4. Have IPFS running in your local user folder (under $HOME/.ipfs).
> >
> > Signed-off-by: Mark Gaiser <markg85 at gmail.com>
> > ---
> > configure | 2 +
> > doc/protocols.texi | 30 ++++
> > libavformat/Makefile | 2 +
> > libavformat/ipfsgateway.c | 328 ++++++++++++++++++++++++++++++++++++++
> > libavformat/protocols.c | 2 +
> > 5 files changed, 364 insertions(+)
> > create mode 100644 libavformat/ipfsgateway.c
> >
> > diff --git a/configure b/configure
> > index e4d36aa639..55af90957a 100755
> > --- a/configure
> > +++ b/configure
> > @@ -3579,6 +3579,8 @@ udp_protocol_select="network"
> > udplite_protocol_select="network"
> > unix_protocol_deps="sys_un_h"
> > unix_protocol_select="network"
> > +ipfs_protocol_select="https_protocol"
> > +ipns_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
> >
> > + at 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:
> > + at example
> > +ffplay ipfs://QmbGtJg23skhvFmu9mJiePVByhfzu5rwo74MEkVDYAmF5T
> > + at end example
> > +
> > +Or the IPNS protocol (IPNS is mutable IPFS):
> > + at example
> > +ffplay ipns://QmbGtJg23skhvFmu9mJiePVByhfzu5rwo74MEkVDYAmF5T
> > + at end example
> > +
> > +You can also change the gateway to be used:
> > +
> > + at table @option
> > +
> > + at 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.
> > +
> > + at end table
> >
> > @c man end PROTOCOLS
> > diff --git a/libavformat/Makefile b/libavformat/Makefile
> > index d7182d6bd8..e3233fd7ac 100644
> > --- a/libavformat/Makefile
> > +++ b/libavformat/Makefile
> > @@ -660,6 +660,8 @@ 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) += ipfsgateway.o
> > +OBJS-$(CONFIG_IPNS_PROTOCOL) += ipfsgateway.o
> > TLS-OBJS-$(CONFIG_GNUTLS) += tls_gnutls.o
> > TLS-OBJS-$(CONFIG_LIBTLS) += tls_libtls.o
> > TLS-OBJS-$(CONFIG_MBEDTLS) += tls_mbedtls.o
> > diff --git a/libavformat/ipfsgateway.c b/libavformat/ipfsgateway.c
> > new file mode 100644
> > index 0000000000..725cc5e474
> > --- /dev/null
> > +++ b/libavformat/ipfsgateway.c
> > @@ -0,0 +1,328 @@
> > +/*
> > + * IPFS and IPNS protocol support through IPFS Gateway.
> > + * Copyright (c) 2022 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/avstring.h"
> > +#include "libavutil/opt.h"
> > +#include "url.h"
> > +#include <sys/stat.h>
> > +
> > +typedef struct IPFSGatewayContext {
> > + AVClass *class;
> > + URLContext *inner;
> > + // Is filled by the -gateway argument and not changed after.
> > + char *gateway;
> > + // If the above gateway is non null, it will be copied into this
> > buffer.
> > + // Else this buffer will contain the auto detected gateway.
> > + // In either case, the gateway to use will be in this buffer.
> > + char gateway_buffer[PATH_MAX];
> > +} IPFSGatewayContext;
> > +
> > +// A best-effort way to find the IPFS gateway.
> > +// Only the most appropiate gateway is set. It's not actually requested
> > +// (http call) to prevent a potential slowdown in startup. A potential
> > timeout
> > +// is handled by the HTTP protocol.
> > +static int populate_ipfs_gateway(URLContext *h)
> > +{
> > + IPFSGatewayContext *c = h->priv_data;
> > + char ipfs_full_data_folder[PATH_MAX];
> > + char ipfs_gateway_file[PATH_MAX];
> > + struct stat st;
> > + int stat_ret = 0;
> > + int ret = AVERROR(EINVAL);
> > + FILE *gateway_file = NULL;
> > +
> > + // Test $IPFS_GATEWAY.
> > + if (getenv("IPFS_GATEWAY") != NULL) {
> > + if (snprintf(c->gateway_buffer, sizeof(c->gateway_buffer), "%s",
> > + getenv("IPFS_GATEWAY")) >=
> > sizeof(c->gateway_buffer)) {
> > + av_log(h, AV_LOG_WARNING, "The IPFS_GATEWAY environment
> > variable "
> > + "exceeds the maximum length. "
> > + "We allow a max of %zu
> > characters\n",
> > + sizeof(c->gateway_buffer));
> > + ret = AVERROR(EINVAL);
> > + goto err;
> > + }
> > +
> > + ret = 1;
> > + goto err;
> > + } else
> > + av_log(h, AV_LOG_DEBUG, "$IPFS_GATEWAY is empty.\n");
> > +
> > + // We need to know the IPFS folder to - eventually - read the
> > contents of
> > + // the "gateway" file which would tell us the gateway to use.
> > + if (getenv("IPFS_PATH") == NULL) {
> > + av_log(h, AV_LOG_DEBUG, "$IPFS_PATH is empty.\n");
> > +
> > + // Try via the home folder.
> > + if (getenv("HOME") == NULL) {
> > + av_log(h, AV_LOG_WARNING, "$HOME appears to be empty.\n");
> > + ret = AVERROR(EINVAL);
> > + goto err;
> > + }
> > +
> > + // Verify the composed path fits.
> > + if (snprintf(ipfs_full_data_folder, sizeof(ipfs_full_data_folder),
> > + "%s/.ipfs/", getenv("HOME")) >=
> > sizeof(ipfs_full_data_folder)) {
> > + av_log(h, AV_LOG_WARNING, "The IPFS data path exceeds the "
> > + "max path length (%zu)\n",
> > + sizeof(ipfs_full_data_folder));
> > + ret = AVERROR(EINVAL);
> > + goto err;
> > + }
> > +
> > + // Stat the folder.
> > + // It should exist in a default IPFS setup when run as local user.
> > +#ifndef _WIN32
> > + stat_ret = stat(ipfs_full_data_folder, &st);
> > +#else
> > + stat_ret = win32_stat(ipfs_full_data_folder, &st);
> > +#endif
> > + if (stat_ret < 0) {
> > + av_log(h, AV_LOG_INFO, "Unable to find IPFS folder. We
> > tried:\n");
> > + av_log(h, AV_LOG_INFO, "- $IPFS_PATH, which was empty.\n");
> > + av_log(h, AV_LOG_INFO, "- $HOME/.ipfs (full uri: %s) which
> > doesn't exist.\n", ipfs_full_data_folder);
> > + ret = AVERROR(ENOENT);
> > + goto err;
> > + }
> > + } else {
> > + if (snprintf(ipfs_full_data_folder,
> > sizeof(ipfs_full_data_folder), "%s",
> > + getenv("IPFS_PATH")) >= sizeof(ipfs_full_data_folder)) {
> > + av_log(h, AV_LOG_WARNING, "The IPFS_PATH environment variable
> > "
> > + "exceeds the maximum length. "
> > + "We allow a max of %zu
> > characters\n",
> > + sizeof(c->gateway_buffer));
> > + ret = AVERROR(EINVAL);
> > + goto err;
> > + }
> > +
> > + }
> > +
> > + // Copy the fully composed gateway path into ipfs_gateway_file.
> > + if (snprintf(ipfs_gateway_file, sizeof(ipfs_gateway_file),
> > "%sgateway",
> > + ipfs_full_data_folder) >= sizeof(ipfs_gateway_file)) {
> > + av_log(h, AV_LOG_WARNING, "The IPFS gateway file path exceeds "
> > + "the max path length (%zu)\n",
> > + sizeof(ipfs_gateway_file));
> > + ret = AVERROR(ENOENT);
> > + goto err;
> > + }
> > +
> > + // Get the contents of the gateway file.
> > + gateway_file = av_fopen_utf8(ipfs_gateway_file, "r");
> > + if (!gateway_file) {
> > + av_log(h, AV_LOG_WARNING, "The IPFS gateway file (full uri: %s)
> > doesn't exist. "
> > + "Is the gateway enabled?\n",
> > + ipfs_gateway_file);
> > + ret = AVERROR(ENOENT);
> > + goto err;
> > + }
> > +
> > + // Read a single line (fgets stops at new line mark).
> > + if (!fgets(c->gateway_buffer, sizeof(c->gateway_buffer) - 1,
> > gateway_file)) {
> > + av_log(h, AV_LOG_WARNING, "Unable to read from file (full uri:
> > %s).\n",
> > + ipfs_gateway_file);
> > + ret = AVERROR(ENOENT);
> > + goto err;
> > + }
> > +
> > + // Replace first occurence of end of line with \0
> > + c->gateway_buffer[strcspn(c->gateway_buffer, "\r\n")] = 0;
> > +
> > + // If strlen finds anything longer then 0 characters then we have a
> > + // potential gateway url.
> > + if (*c->gateway_buffer == '\0') {
> > + av_log(h, AV_LOG_WARNING, "The IPFS gateway file (full uri: %s)
> > appears to be empty. "
> > + "Is the gateway started?\n",
> > + ipfs_gateway_file);
> > + ret = AVERROR(EILSEQ);
> > + goto err;
> > + } else {
> > + // We're done, the c->gateway_buffer has something that looks
> > valid.
> > + ret = 1;
> > + goto err;
> > + }
> > +
> > +err:
> > + if (gateway_file)
> > + fclose(gateway_file);
> > +
> > + return ret;
> > +}
> > +
> > +static int translate_ipfs_to_http(URLContext *h, const char *uri,
> > + int flags, AVDictionary **options)
> > +{
> > + const char *ipfs_cid;
> > + char *fulluri = NULL;
> > + int ret;
> > + IPFSGatewayContext *c = h->priv_data;
> > +
> > + // Test for ipfs://, ipfs:, ipns:// and ipns:. This prefix is
> > stripped from
> > + // the string leaving just the CID in ipfs_cid.
> > + int is_ipfs = av_stristart(uri, "ipfs://", &ipfs_cid);
> > + int is_ipns = av_stristart(uri, "ipns://", &ipfs_cid);
> > +
> > + // We must have either ipns or ipfs.
> > + if (!is_ipfs && !is_ipns) {
> > + ret = AVERROR(EINVAL);
> > + av_log(h, AV_LOG_WARNING, "Unsupported url %s\n", uri);
> > + goto err;
> > + }
> > +
> > + // If the CID has a length greater then 0 then we assume we have a
> > proper working one.
> > + // It could still be wrong but in that case the gateway should save
> > us and
> > + // ruturn a 403 error. The http protocol handles this.
> > + if (strlen(ipfs_cid) < 1) {
> > + av_log(h, AV_LOG_WARNING, "A CID must be provided.\n");
> > + ret = AVERROR(EILSEQ);
> > + goto err;
> > + }
> > +
> > + // Populate c->gateway_buffer with whatever is in c->gateway
> > + if (c->gateway != NULL) {
> > + if (snprintf(c->gateway_buffer, sizeof(c->gateway_buffer), "%s",
> > + c->gateway) >= sizeof(c->gateway_buffer)) {
> > + av_log(h, AV_LOG_WARNING, "The -gateway parameter is too
> > long. "
> > + "We allow a max of %zu
> > characters\n",
> > + sizeof(c->gateway_buffer));
> > + ret = AVERROR(EINVAL);
> > + goto err;
> > + }
> > + } else {
> > + // Populate the IPFS gateway if we have any.
> > + // If not, inform the user how to properly set one.
> > + ret = populate_ipfs_gateway(h);
> > +
> > + if (ret < 1) {
> > + // We fallback on dweb.link (managed by Protocol Labs).
> > + snprintf(c->gateway_buffer, sizeof(c->gateway_buffer), "
> > https://dweb.link");
> > +
> > + av_log(h, AV_LOG_WARNING, "IPFS does not appear to be
> > running. "
> > + "You’re now using the public
> > gateway at dweb.link.\n");
> > + av_log(h, AV_LOG_INFO, "Installing IPFS locally is
> > recommended to "
> > + "improve performance and reliability, "
> > + "and not share all your activity with
> > a single IPFS gateway.\n"
> > + "There are multiple options to define this gateway.\n"
> > + "1. Call ffmpeg with a gateway param, "
> > + "without a trailing slash: -gateway
> > <url>.\n"
> > + "2. Define an $IPFS_GATEWAY environment variable with
> > the "
> > + "full HTTP URL to the gateway "
> > + "without trailing forward slash.\n"
> > + "3. Define an $IPFS_PATH environment variable "
> > + "and point it to the IPFS data path "
> > + "- this is typically ~/.ipfs\n");
> > + }
> > + }
> > +
> > + // Test if the gateway starts with either http:// or https://
> > + if (av_stristart(c->gateway_buffer, "http://", NULL) == 0
> > + && av_stristart(c->gateway_buffer, "https://", NULL) == 0) {
> > + av_log(h, AV_LOG_WARNING, "The gateway URL didn't start with
> > http:// or "
> > + "https:// and is therefore
> > invalid.\n");
> > + ret = AVERROR(EILSEQ);
> > + goto err;
> > + }
> > +
> > + // Concatenate the url.
> > + // This ends up with something like: http://localhost:8080/ipfs/Qm...
> > ..
> > + // The format of "%s%s%s%s" is the following:
> > + // 1st %s = The gateway.
> > + // 2nd %s = If the gateway didn't end in a slash, add a "/".
> > Otherwise it's an empty string
> > + // 3rd %s = Either ipns/ or ipfs/.
> > + // 4th %s = The IPFS CID (Qm..., bafy..., ...).
> > + fulluri = av_asprintf("%s%s%s%s",
> > + c->gateway_buffer,
> > + (c->gateway_buffer[strlen(c->gateway_buffer) -
> > 1] == '/') ? "" : "/",
> > + (is_ipns) ? "ipns/" : "ipfs/",
> > + ipfs_cid);
> > +
> > + if (!fulluri) {
> > + av_log(h, AV_LOG_ERROR, "Failed to compose the URL\n");
> > + ret = AVERROR(ENOMEM);
> > + goto err;
> > + }
> > +
> > + // Pass the URL back to FFMpeg's protocol handler.
> > + ret = ffurl_open_whitelist(&c->inner, fulluri, flags,
> > + &h->interrupt_callback, options,
> > + h->protocol_whitelist,
> > + h->protocol_blacklist, h);
> > + if (ret < 0) {
> > + av_log(h, AV_LOG_WARNING, "Unable to open resource: %s\n",
> > fulluri);
> > + goto err;
> > + }
> > +
> > +err:
> > + av_free(fulluri);
> > + return ret;
> > +}
> > +
> > +static int ipfs_read(URLContext *h, unsigned char *buf, int size)
> > +{
> > + IPFSGatewayContext *c = h->priv_data;
> > + return ffurl_read(c->inner, buf, size);
> > +}
> > +
> > +static int64_t ipfs_seek(URLContext *h, int64_t pos, int whence)
> > +{
> > + IPFSGatewayContext *c = h->priv_data;
> > + return ffurl_seek(c->inner, pos, whence);
> > +}
> > +
> > +static int ipfs_close(URLContext *h)
> > +{
> > + IPFSGatewayContext *c = h->priv_data;
> > + return ffurl_closep(&c->inner);
> > +}
> > +
> > +#define OFFSET(x) offsetof(IPFSGatewayContext, x)
> > +
> > +static const AVOption options[] = {
> > + {"gateway", "The gateway to ask for IPFS data.", OFFSET(gateway),
> > AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_DECODING_PARAM},
> > + {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 = translate_ipfs_to_http,
> > + .url_read = ipfs_read,
> > + .url_seek = ipfs_seek,
> > + .url_close = ipfs_close,
> > + .priv_data_size = sizeof(IPFSGatewayContext),
> > + .priv_data_class = &ipfs_context_class,
> > +};
> > +
> > +const URLProtocol ff_ipns_protocol = {
> > + .name = "ipns",
> > + .url_open2 = translate_ipfs_to_http,
> > + .url_read = ipfs_read,
> > + .url_seek = ipfs_seek,
> > + .url_close = ipfs_close,
> > + .priv_data_size = sizeof(IPFSGatewayContext),
> > + .priv_data_class = &ipfs_context_class,
> > +};
> > diff --git a/libavformat/protocols.c b/libavformat/protocols.c
> > index d07563cd0c..6ee62a598a 100644
> > --- a/libavformat/protocols.c
> > +++ b/libavformat/protocols.c
> > @@ -71,6 +71,8 @@ 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
> >
> >
> Ping, even though the message is just here for mere minutes.
>
> As of the very day i'm now sending updated patches for this for exactly 2
> months. I started on Feb. 1st.
> With the last round of changes (Thanx Andreas!) I feel really confident
> that this is now at the very least good quality code ready for prime time!
> IPFS support is now also working by default, even when you don't have IPFS
> at all (in here since a few patches ago).
> Yeah, I feel really good about it now!
>
> I'd very much appreciate it if this could finally be merged. I promise I'm
> staying around to fix bugs if there are still bugs to be fixed and will
> respond swiftly :)
>
> But... I'd really really really like to be done with it for now.
> I don't know when ffmpeg 5.1 is going to be released but having IPFS
> support in there would be absolutely awesome! And would help me greatly in
> continuing the development to support IPFS in mpv, KODI and VLC.
Not building on mingw64
CC libavformat/ipfsgateway.o
src/libavformat/ipfsgateway.c: In function ‘populate_ipfs_gateway’:
src/libavformat/ipfsgateway.c:96:20: error: implicit declaration of function ‘win32_stat’; did you mean ‘wstat’? [-Werror=implicit-function-declaration]
stat_ret = win32_stat(ipfs_full_data_folder, &st);
^~~~~~~~~~
wstat
cc1: some warnings being treated as errors
src/ffbuild/common.mak:78: recipe for target 'libavformat/ipfsgateway.o' failed
make: *** [libavformat/ipfsgateway.o] Error 1
maybe you removed some #include that was actually needed ? (if this code didnt
chaneg because it did build previosuly)
thx
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
The bravest are surely those who have the clearest vision
of what is before them, glory and danger alike, and yet
notwithstanding go out to meet it. -- Thucydides
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