[FFmpeg-devel] [PATCH v10 1/1] avformat: Add IPFS protocol support.
Mark Gaiser
markg85 at gmail.com
Thu Mar 31 19:01:27 EEST 2022
On Wed, Mar 30, 2022 at 5:16 PM Mark Gaiser <markg85 at gmail.com> wrote:
>
>
> On Wed, Mar 30, 2022 at 3:57 PM Andreas Rheinhardt <
> andreas.rheinhardt at outlook.com> wrote:
>
>> Mark Gaiser:
>> > On Wed, Mar 30, 2022 at 2:21 PM Andreas Rheinhardt <
>> > andreas.rheinhardt at outlook.com> wrote:
>> >
>> >> Mark Gaiser:
>> >>> 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 | 309
>> ++++++++++++++++++++++++++++++++++++++
>> >>> libavformat/protocols.c | 2 +
>> >>> 5 files changed, 345 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..1a039589c0
>> >>> --- /dev/null
>> >>> +++ b/libavformat/ipfsgateway.c
>> >>> @@ -0,0 +1,309 @@
>> >>> +/*
>> >>> + * 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 "avformat.h"
>> >>> +#include "libavutil/avassert.h"
>> >>
>> >> Unused.
>> >>
>> >>> +#include "libavutil/avstring.h"
>> >>> +#include "libavutil/internal.h"
>> >>> +#include "libavutil/opt.h"
>> >>> +#include "libavutil/tree.h"
>> >>
>> >> ?
>> >>
>> >
>> > This whole include part can be cleaned up much more.
>> > Just having these:
>> > #include "libavutil/avstring.h"
>> > #include "libavutil/opt.h"
>> > #include "url.h"
>> > #include <sys/stat.h>
>> >
>> > is enough.
>> >
>> >
>> >>> +#include <fcntl.h>
>> >>> +#if HAVE_IO_H
>> >>> +#include <io.h>
>> >>> +#endif
>> >>> +#if HAVE_UNISTD_H
>> >>> +#include <unistd.h>
>> >>> +#endif
>> >>> +#include "os_support.h"
>> >>> +#include "url.h"
>> >>> +#include <stdlib.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).
>> >>> + fgets(c->gateway_buffer, sizeof(c->gateway_buffer) - 1,
>> >> gateway_file);
>> >>> +
>> >>> + // Replace the last char with \0
>> >>> + c->gateway_buffer[sizeof(c->gateway_buffer) - 1] = 0;
>> >>> +
>> >>> + // Replace first occurence of end of line with \0
>> >>> + c->gateway_buffer[strcspn(c->gateway_buffer, "\r")] = 0;
>> >>> + c->gateway_buffer[strcspn(c->gateway_buffer, "\n")] = 0;
>> >>
>> >> If the buffer contains both \r and \n and the first \n precedes the
>> >> first \r, then the above zeroes both the first \r and the first \n. If
>> >> it is enough to only zero the first newline, then this can be
>> simplified
>> >> to "c->gateway_buffer[strcspn(c->gateway_buffer, "\r\n")] = 0;".
>> >>
>> >
>> > It used to be in your suggested simplified approach.
>> > It was then suggested to split it because of new line differences
>> > on different platforms. This was supposed to catch "everything".
>> >
>> > I prefer to keep this as-is now.
>> >
>>
>> Is it intended to use what is between the first \n and the first \r
>> lateron although this data will be after the '\0' after this? That would
>> be very weird.
>>
>
> You have to elaborate on that as that sounds really wrong to me.
>
> If I'm correct a file doesn't start with either \r or \n. Unless you have
> intentional line breaks.
> It ends with those, not starts. I'm just going to ignore \r for now for
> brevity.
>
> So if you have:
> \n<your gateway>\n
>
> Would be translated to:
> \0<your gateway>\n
>
> Then indeed you won't get a gateway because it's intended that your first
> line is that gateway.
>
> It must be in this format:
> <your gateway>\n
>
> or without a newline
> <your gateway>
>
> There is no blank line trimming to fix user screwups.
> Users are not intended to touch that file anyhow. It's auto-generated by
> IPFS and removed once it shuts down.
>
>
>> >
>> >>> +
>> >>> + // If strlen finds anything longer then 0 characters then we
>> have a
>> >>> + // potential gateway url.
>> >>> + if (strlen(c->gateway_buffer) < 1) {
>> >>
>> >> if (*c->gateway_buffer == '\0')
>> >>
>> >
>> > Is that a style difference or an actual behavior difference?
>> >
>>
>> The former would call strlen to check whether a string is empty (unless
>> the compiler optimizes it away). No actual behaviour difference exists.
>> But it is nevertheless more than a style difference.
>>
>
> Fixed locally.
>
>>
>> >
>> >>
>> >>> + 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));
>> >>
>> >> We typically use SIZE_SPECIFIER instead of z for compatibility with
>> >> ancient versions of MSVC.
>> >> (I don't know whether there is any supported version of MSVC that
>> >> doesn't support z; I don't use MSVC myself.)
>> >>
>> >
>> > Here too I was explicitly suggested to use %zu (when I was using - I
>> think
>> > - %lu before).
>> > So I assume that the ancient MSVC version you're referring to is
>> probably
>> > not supported anymore from an ffmpeg compiler requirement point of view?
>> >
>> > Should i now change all "%zu" to "%"SIZE_SPECIFIER (this does not make
>> it
>> > neater nor shorter with the 80 char line limit).
>> > Is this change required?
>>
>> As said: It is for compatibility with ancient versions of MSVC. But I
>> don't know whether any of the actually supported versions of MSVC still
>> need it.
>>
>> >
>> > If it is, what _exactly_ do i need to change it in? I see a
>> > couple different SIZE_SPECIFIER prefixes. I have no clue what to use
>> here.
>>
>> There is only one SIZE_SPECIFIER, namely SIZE_SPECIFIER; the
>> PTRDIFF_SPECIFIER (or whatever you see) is obviously not the thing to
>> use for size_t.
>>
>> I see some:
> %"SIZE_SPECIFIER"
>
> But also like this:
> %8"SIZE_SPECIFIER
> %5"SIZE_SPECIFIER
>
> I'm assuming they are for clipping?
>
> I really don't like having to change it to this as it:
> - Uglifies the code (and i doubt if it's even needed)
> - Directly contradicts earlier feedback
> - And due to the above gives me a feeling of wasting time
> - Fine to change it but I hope there isn't another person popping up with
> a question to change it yet again....
>
>
>> >
>> >
>> >>> + 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");
>> >>> + av_log(h, AV_LOG_INFO, "There are multiple options to
>> >> define this gateway.\n");
>> >>> + av_log(h, AV_LOG_INFO, "1. Call ffmpeg with a gateway
>> >> param, without a trailing slash: -gateway <url>.\n");
>> >>> + av_log(h, AV_LOG_INFO, "2. Define an $IPFS_GATEWAY
>> >> environment variable with the full HTTP URL to the gateway without
>> trailing
>> >> forward slash.\n");
>> >>> + av_log(h, AV_LOG_INFO, "3. Define an $IPFS_PATH
>> environment
>> >> variable and point it to the IPFS data path - this is typically
>> ~/.ipfs\n");
>> >>
>> >> All those AV_LOG_INFO can be combined which has the advantage that the
>> >> logs can't be teared apart (which they can now if something else logs
>> at
>> >> the same time); furthermore, this would also decrease codesize.
>> >>
>> >
>> > Do you have an example of where that's happening?
>> >
>>
>> It can happen any time you have multiple threads using av_log at the
>> same time. Given that your statements are supposed to be full lines, it
>> is not that bad if it happens here, but it is nevertheless suboptimal.
>>
>
> I meant a multi-line av_log example ;) But yeah, I get how threading could
> screw this up.
>
>>
>> >>
>> >>> + }
>> >>> + }
>> >>> +
>> >>> + // 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);
>> >>
>> >> Missing allocation check.
>> >>
>> >
>> > Ah
>> > Fixed it locally.
>> >
>> >
>> >>
>> >>> +
>> >>> + // Pass the URL back to FFMpeg's protocol handler.
>> >>> + if ((ret = ffurl_open_whitelist(&c->inner, fulluri, flags,
>> >>> + &h->interrupt_callback, options,
>> >>> + h->protocol_whitelist,
>> >>> + h->protocol_blacklist, h))
>> >>> + < 0) {
>> >>
>> >> Weird formatting; why don't you just use
>> >> ret = ffurl_open_whitelist(...);
>> >> if (ret < 0) {
>> >>
>> >
>> > Fixed.
>> >
>> >
>> >>
>> >>> + 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"
>> >>>
>> >>
>> >>
>> > Thank you very much for your review!
>> > Please do hit me back with a reply on the questions I have still open.
>> >
>> > I'm honestly quite done with patching this over and over again (it's
>> open
>> > for months now) so I'd like to put the pace in these fixes and send an
>> > updated version today.
>> >
>>
>>
Ping Andreas, i'm waiting for your response on the questions above before i
send an updated patch.
Also ping for Tomas with regards to the same questions (%zu vs
SIZE_SPECIFIER and the merging of \r\n which i had split based on your
feedback)
Let's keep the pace :)
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