Inform the user about how to set a gateway if none could be found.
Signed-off-by: Mark Gaiser <mark...@gmail.com>
---
libavformat/ipfs.c | 159 +++++++++++++++++++++++++++++++++++++++++----
1 file changed, 147 insertions(+), 12 deletions(-)
diff --git a/libavformat/ipfs.c b/libavformat/ipfs.c
index 22487c6cc8..8f6f91d85d 100644
--- a/libavformat/ipfs.c
+++ b/libavformat/ipfs.c
@@ -44,31 +44,166 @@ typedef struct Context {
char *gateway;
} Context;
+// 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
+// potential slowdown in startup. A potential timeout is handled by the HTTP
protocol.
+//
+// When done and the return value is 1, a potential IPFS Gateway is set in the
gateway
+// variable in the inner URLContext.
+static int populate_ipfs_gateway(URLContext *h)
+{
+ Context *c = h->priv_data;
+ char *home_folder;
+ const char *ipfs_data_folder = "/.ipfs/";
+ char *ipfs_full_data_folder;
+ char *ipfs_gateway_file;
+ struct stat st;
+ int stat_ret = 0;
+ FILE *gateway_file;
+ char gateway_file_data[1000];
+
+ // First, test if there already is a path in c->gateway. If it is then it
was provided as
+ // cli arument and should be used. It takes precdence.
+ if (c->gateway != NULL) {
+ return 1;
+ }
+
+ // Test $IPFS_GATEWAY
+ c->gateway = getenv("IPFS_GATEWAY");
+ if (c->gateway) {
+ return 1;
+ } else {
+ av_log(h, AV_LOG_DEBUG, "$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.
+ ipfs_full_data_folder = getenv("IPFS_PATH");
+
+ if (!ipfs_full_data_folder) {
+ av_log(h, AV_LOG_DEBUG, "$IPFS_PATH is empty.\n");
+
+ // Try via the home folder
+ home_folder = getenv("HOME");
+ ipfs_full_data_folder = malloc(strlen(home_folder) +
strlen(ipfs_data_folder) + 1);
+ strcpy(ipfs_full_data_folder, home_folder);
+ strcat(ipfs_full_data_folder, ipfs_data_folder);
+
+ // 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_DEBUG, "Unable to find IPFS folder. We tried:\n");
+ av_log(h, AV_LOG_DEBUG, "- $IPFS_PATH, which was empty.\n");
+ av_log(h, AV_LOG_DEBUG, "- $HOME/.ipfs (full uri: %s) which
doesn't exist.\n", ipfs_full_data_folder);
+ return -1;
+ }
+ }
+
+ ipfs_gateway_file = malloc(strlen(ipfs_full_data_folder) +
strlen("gateway") + 1);
+ strcpy(ipfs_gateway_file, ipfs_full_data_folder);
+ strcat(ipfs_gateway_file, "gateway");
+
+ // Stat the gateway file. If it doesn't exist we have no gateway. If it
does, we might have one.
+#ifndef _WIN32
+ stat_ret = stat(ipfs_gateway_file, &st);
+#else
+ stat_ret = win32_stat(ipfs_gateway_file, &st);
+#endif
+ if (stat_ret < 0) {
+ av_log(h, AV_LOG_ERROR, "The IPFS gateway file (full uri: %s) doesn't
exist. Is the gateway enabled?\n", ipfs_gateway_file);
+ return -1;
+ }
+
+ // Get the contents of the gateway file
+ gateway_file = av_fopen_utf8(ipfs_gateway_file, "r");
+ if (!gateway_file) {
+ av_log(h, AV_LOG_ERROR, "Unable to open the IPFS gateway file (full
uri: %s).\n", ipfs_gateway_file);
+ return -1;
+ }
+
+ fscanf(gateway_file, "%[^\n]", gateway_file_data);
+ fclose(gateway_file);
+
+ if ((st.st_size < 1) || (strlen(gateway_file_data) < 1)) {
+ av_log(h, AV_LOG_ERROR, "The IPFS gateway file (full uri: %s) appears
to be empty. Is the gateway started?\n", ipfs_gateway_file);
+ return -1;
+ }
+
+ // Copy the gateway url into c->gateway
+ c->gateway = malloc(strlen(gateway_file_data) + 1);
+ strcpy(c->gateway, gateway_file_data);
+ if (c->gateway) {
+ return 1;
+ } else {
+ av_log(h, AV_LOG_DEBUG, "Unknown error in the IPFS gateway file.\n");
+ }
+
+ return -1;
+}
+
+// For now just makes sure that the gateway ends in url we expect. Like
http://localhost:8080/.
+// Explicitly with the traling slash.
+static void sanitize_ipfs_gateway(URLContext *h)
+{
+ Context *c = h->priv_data;
+ const char last_gateway_char = c->gateway[strlen(c->gateway) - 1];
+ char *sanitized_gateway = c->gateway;
+
+ if (last_gateway_char != '/') {
+ sanitized_gateway = malloc(strlen(c->gateway) + 2);
+ strcpy(sanitized_gateway, c->gateway);
+ strcat(sanitized_gateway, "/");
+ }
+
+ c->gateway = sanitized_gateway;
+}
+
static int ipfs_open(URLContext *h, const char *uri, int flags, AVDictionary
**options)
{
- const char *gatewaysuffix;
- const char *protocolPathSuffix = "ipfs/";
+ const char *gateway_suffix;
+ const char *protocol_path_suffix = "ipfs/";
int ret = 0;
Context *c = h->priv_data;
- int isIpfs = (av_strstart(uri, "ipfs://", &gatewaysuffix) ||
av_strstart(uri, "ipfs:", &gatewaysuffix));
- int isIpns = (av_strstart(uri, "ipns://", &gatewaysuffix) ||
av_strstart(uri, "ipns:", &gatewaysuffix));
-
- if (!isIpfs && !isIpns) {
+ int is_ipfs = (av_strstart(uri, "ipfs://", &gateway_suffix) ||
av_strstart(uri, "ipfs:", &gateway_suffix));
+ int is_ipns = (av_strstart(uri, "ipns://", &gateway_suffix) ||
av_strstart(uri, "ipns:", &gateway_suffix));
+
+ // Populate the IPFS gateway if we have any.
+ // If not, inform the user how to properly set one.
+ if (populate_ipfs_gateway(h) < 0) {
+ av_log(h, AV_LOG_ERROR, "No IPFS gateway was set. Make sure a local
IPFS instance is running.\n");
+ av_log(h, AV_LOG_INFO, "There are multiple options to define this
gateway. The below options are in order of precedence:\n");
+ av_log(h, AV_LOG_INFO, "1. Define a -gateway <url> to the gateway
without trailing forward slash.\n");
+ av_log(h, AV_LOG_INFO, "2. Define $IPFS_GATEWAY with the full http
link to the gateway without trailing forward slash.\n");
+ av_log(h, AV_LOG_INFO, "3. Define $IPFS_PATH and point it to the IPFS
data path.\n");
+ av_log(h, AV_LOG_INFO, "4. Have IPFS running in your local user folder
(under $HOME/.ipfs).\n");
+ av_log(h, AV_LOG_INFO, "In all path cases, a file named gateway is
expected. See https://github.com/ipfs/specs/issues/261 for more
information.\n");
+ ret = AVERROR(EINVAL);
+ goto err;
+ }
+
+ // Sanitize the gateway to a format we expect.
+ sanitize_ipfs_gateway(h);
+
+ // We must have either ipns or ipfs.
+ if (!is_ipfs && !is_ipns) {
ret = AVERROR(EINVAL);
av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri);
goto err;
}
// If we have IPNS, update the protocol
- if (isIpns) {
- protocolPathSuffix = "ipns/";
+ if (is_ipns) {
+ protocol_path_suffix = "ipns/";
}
// Concatenate the url. This ends up with something like:
http://localhost:8080/ipfs/Qm.....
- c->fulluri = malloc(strlen(c->gateway) + strlen(protocolPathSuffix) +
strlen(gatewaysuffix) + 1);
+ c->fulluri = malloc(strlen(c->gateway) + strlen(protocol_path_suffix) +
strlen(gateway_suffix) + 1);
strcpy(c->fulluri, c->gateway);
- strcat(c->fulluri, protocolPathSuffix);
- strcat(c->fulluri, gatewaysuffix);
+ strcat(c->fulluri, protocol_path_suffix);
+ strcat(c->fulluri, gateway_suffix);
// Pass the URL back to FFMpeg's protocol handler.
if ((ret = ffurl_open_whitelist(&c->inner, c->fulluri, flags,
@@ -115,7 +250,7 @@ static int ipfs_close(URLContext *h)
#define OFFSET(x) offsetof(Context, x)
static const AVOption options[] = {
- {"gateway", "The gateway to ask for IPFS data.", OFFSET(gateway),
AV_OPT_TYPE_STRING, {.str = "http://localhost:8080/"}, 0, 0,
AV_OPT_FLAG_DECODING_PARAM },
+ {"gateway", "The gateway to ask for IPFS data.", OFFSET(gateway),
AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_DECODING_PARAM },
{NULL},
};
--
2.35.1
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