Le septidi 7 thermidor, an CCXXIII, Stephan Holljes a écrit :
> Signed-off-by: Stephan Holljes <klaxa1...@googlemail.com>
> ---
> doc/examples/Makefile | 1 +
> doc/examples/http_multiclient.c | 163
> ++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 164 insertions(+)
> create mode 100644 doc/examples/http_multiclient.c
> Changes since last version:
> - Changed license
> - Use simpler code to communicate with the library.
>
> diff --git a/doc/examples/Makefile b/doc/examples/Makefile
> index 9699f11..8c9501b 100644
> --- a/doc/examples/Makefile
> +++ b/doc/examples/Makefile
> @@ -18,6 +18,7 @@ EXAMPLES= avio_list_dir \
> extract_mvs \
> filtering_video \
> filtering_audio \
> + http_multiclient \
> metadata \
> muxing \
> remuxing \
> diff --git a/doc/examples/http_multiclient.c b/doc/examples/http_multiclient.c
> new file mode 100644
> index 0000000..84fc739
> --- /dev/null
> +++ b/doc/examples/http_multiclient.c
> @@ -0,0 +1,163 @@
> +/*
> + * Copyright (c) 2015 Stephan Holljes
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> copy
> + * of this software and associated documentation files (the "Software"), to
> deal
> + * in the Software without restriction, including without limitation the
> rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +/**
> + * @file
> + * libavformat multi-client network API usage example.
> + *
> + * @example http_multiclient.c
> + * This example will serve a file without decoding or demuxing it over http.
> + * Multiple clients can connect and will receive the same file.
> + */
> +
> +#include <libavformat/avformat.h>
> +#include <libavutil/opt.h>
> +#include <unistd.h>
> +
> +void process_client(AVIOContext *client, const char *in_uri)
> +{
> + AVIOContext *input = NULL;
> + uint8_t buf[1024];
> + int ret, n, reply_code;
> + char *resource = NULL;
> + while ((ret = avio_handshake(client)) > 0) {
> + av_log(client, AV_LOG_TRACE, "checking for resource\n");
> + av_opt_get(client, "resource", AV_OPT_SEARCH_CHILDREN, &resource);
> + if (resource && strlen(resource)) {
> + resource++;
> + av_log(client, AV_LOG_TRACE, "got resource: %s (%lu)\n",
> resource, strlen(resource));
> + break;
> + }
> + }
> +
> + if (ret < 0)
> + goto end;
> +
> + if (strcmp(resource, in_uri)) {
Nit: at this point, you can not be sure that resource is not null, unless
you trust the library to never set it to the empty string.
And, nit: you accept unintended resources, for example "invalid" for
"/nvalid".
To fix both issues at once, and IMHO make the code a little bit simpler, you
can move the handling outside the loop: in the loop, just
"if (resource) break;", and after the loop, to test the resource, something
like that:
if (!(resource && resource[0] == '/' && !strcmp(resource, in_uri)))
> + reply_code = AVERROR_HTTP_NOT_FOUND;
> + } else {
> + reply_code = 200;
> + }
> + if ((ret = av_opt_set_int(client, "reply_code", reply_code,
> AV_OPT_SEARCH_CHILDREN)) < 0) {
> + av_log(client, AV_LOG_ERROR, "Failed to set reply_code: %s.\n",
> av_err2str(ret));
> + goto end;
> + }
> + av_log(client, AV_LOG_TRACE, "Set reply code to %d\n", reply_code);
> +
> + if ((ret = av_opt_set_int(client, "handshake_finish", 1,
> AV_OPT_SEARCH_CHILDREN)) < 0) {
As stated earlier, this should be the default.
> + av_log(client, AV_LOG_ERROR, "Failed to set handshake_finish:
> %s.\n", av_err2str(ret));
> + goto end;
> + }
> +
> + while ((ret = avio_handshake(client)) > 0);
There is a small API issue here: if for some reason resource never gets set
(for example someone changes the code to use another protocol than HTTP
where it is optional), then the code is calling avio_handshake() extraneous
times.
For that reason, I think it should be ok to call avio_handshake() when the
handshake is already finished. But it should be stated in the doxy:
* If the handshake is already finished, avio_handshake() does nothing and
* returns 0 immediately.
This is also the reason I advise to have a last step constant for when the
handshake is finished.
> +
> + if (ret < 0)
> + goto end;
> +
> + fprintf(stderr, "Handshake performed.\n");
> + if (reply_code != 200)
> + goto end;
> + fprintf(stderr, "Opening input file.\n");
> + if ((ret = avio_open2(&input, in_uri, AVIO_FLAG_READ, NULL, NULL)) < 0) {
> + av_log(input, AV_LOG_ERROR, "Failed to open input: %s: %s.\n",
> in_uri,
> + av_err2str(ret));
> + goto end;
> + }
> + for(;;) {
> + n = avio_read(input, buf, sizeof(buf));
> + if (n < 0) {
> + if (n == AVERROR_EOF)
> + break;
> + av_log(input, AV_LOG_ERROR, "Error reading from input: %s.\n",
> + av_err2str(n));
> + break;
> + }
> + avio_write(client, buf, n);
> + avio_flush(client);
> + }
> +end:
> + fprintf(stderr, "Flushing client\n");
> + avio_flush(client);
> + fprintf(stderr, "Closing client\n");
> + avio_close(client);
> + fprintf(stderr, "Closing input\n");
> + avio_close(input);
> +}
> +
> +int main(int argc, char **argv)
> +{
> + av_log_set_level(AV_LOG_TRACE);
> + AVDictionary *options = NULL;
> + AVIOContext *client = NULL, *server = NULL;
> + const char *in_uri, *out_uri;
> + int ret, pid;
> + if (argc < 3) {
> + printf("usage: %s input http://hostname[:port]\n";
> + "API example program to serve http to multiple clients.\n"
> + "\n", argv[0]);
> + return 1;
> + }
> +
> + in_uri = argv[1];
> + out_uri = argv[2];
> +
> + av_register_all();
> + avformat_network_init();
> +
> + if ((ret = av_dict_set(&options, "listen", "2", 0)) < 0) {
> + fprintf(stderr, "Failed to set listen mode for server: %s\n",
> av_err2str(ret));
> + return ret;
> + }
> + if ((ret = avio_open2(&server, out_uri, AVIO_FLAG_WRITE, NULL,
> &options)) < 0) {
> + fprintf(stderr, "Failed to open server: %s\n", av_err2str(ret));
> + return ret;
> + }
> + fprintf(stderr, "Entering main loop.\n");
> + for(;;) {
> + if ((ret = avio_accept(server, &client)) < 0)
> + goto end;
> + fprintf(stderr, "Accepted client, forking process.\n");
> + // XXX: Since we don't reap our children and don't ignore signals
> + // this produces zombie processes.
> + pid = fork();
> + if (pid < 0) {
> + perror("Fork failed");
> + ret = AVERROR(errno);
> + goto end;
> + }
> + if (pid == 0) {
> + fprintf(stderr, "In child.\n");
> + process_client(client, in_uri);
> + avio_close(server);
> + exit(0);
> + }
> + if (pid > 0)
> + avio_close(client);
> + }
> +end:
> + avio_close(server);
> + if (ret < 0 && ret != AVERROR_EOF) {
> + fprintf(stderr, "Some errors occured: %s\n", av_err2str(ret));
> + return 1;
> + }
> + return 0;
> +}
Regards,
--
Nicolas George
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