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Nginx Video preview

Nginx video preview


Hi !
I have some problem using mattermost through nginx.
Everything works perfectly, I have a certificate, a domain name, port forwarding, but the video preview doesn’t load due to a problem (see picture)


Problem using nginx for video preview

Steps to reproduce

How can we reproduce the issue (what version are you using?)

Version : latest
Machine : VirtualBox Ubuntu 20.04 LTS
SQL base : MySQL
Mail server : None
Other servers running on the machine : yes
TLS : Through Nginx
TLS Certificate : Let’s Encrypt
Nginx : Installing Mattermost on Ubuntu 20.04 LTS — Mattermost 5.33 documentation

Nginx configuration:

server {
  listen 443 ssl http2;
  server_name    mattermost.domain.com ;

  ssl on;
  ssl_certificate /etc/letsencrypt/live/mattermost.domain.com/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/mattermost.domain.com/privkey.pem;
  ssl_session_timeout 1d;
  ssl_protocols TLSv1.2;
  ssl_prefer_server_ciphers on;
  ssl_session_cache shared:SSL:50m;
  # HSTS (ngx_http_headers_module is required) (15768000 seconds = 6 months)
  add_header Strict-Transport-Security max-age=15768000;
  # OCSP Stapling ---
  # fetch OCSP records from URL in ssl_certificate and cache them
  ssl_stapling on;
  ssl_stapling_verify on;

   location / {
       client_max_body_size 5000M;
       proxy_set_header Connection "";
       proxy_set_header Host $http_host;
       proxy_set_header X-Real-IP $remote_addr;
       proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
       proxy_set_header X-Forwarded-Proto $scheme;
       proxy_set_header X-Frame-Options SAMEORIGIN;
       proxy_buffers 256 16k;
       proxy_buffer_size 16k;
       proxy_read_timeout 600s;
       proxy_cache mattermost_cache;
       proxy_cache_revalidate on;
       proxy_cache_min_uses 2;
       proxy_cache_use_stale timeout;
       proxy_cache_lock on;
       proxy_http_version 1.1;
       proxy_pass http://localhost:8065;

  location ~ /api/v[0-9]+/(users/)?websocket$ {
       proxy_set_header Upgrade $http_upgrade;
       proxy_set_header Connection "upgrade";
       client_max_body_size 500M;
       proxy_set_header Host $http_host;
       proxy_set_header X-Real-IP $remote_addr;
       proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
       proxy_set_header X-Forwarded-Proto $scheme;
       proxy_set_header X-Frame-Options SAMEORIGIN;
       proxy_buffers 256 16k;
       proxy_buffer_size 16k;
       client_body_timeout 60;
       send_timeout 300;
       lingering_timeout 5;
       proxy_connect_timeout 90;
       proxy_send_timeout 300;
       proxy_read_timeout 90s;
       proxy_pass http://localhost:8065;

Expected behavior

When I try to watch the preview of the file, it just propose me to download it.
When I tried generating a link, here is what I get in the console:


Failed to load ressource: Plug-in handled load

But first, MM try to open the preview

And then it doesn’t work :frowning:

Observed behavior

It is not a problem with MM because it works perfectly in local mode (without nginx)

1 Like

Hello! This is an Nginx issue, specifically relating to the configured MIME type of the video file type. Basically, with your current configuration, the video format, be that .mp4 or .wav or whatever it is, is being declared as a content type of application/octet-stream, which tells the server that it is a binary file, and it needs to download it. This can be changed, however, to allow the file to load and be played/displayed in-browser, with some changes made to your /etc/nginx/nginx.conf and /etc/nginx/mime.types files.

First, could you provide the full contents of the Nginx configuration file that you set up your reverse proxy in, if it is not all here already, as well as the contents of /etc/nginx/nginx.conf and /etc/nginx/mime.types? This will allow me to find the right lines that need to be changed in all three files, and direct you to them effectively, to make the said changes.

Also, could you specify the file type that is downloading instead of loading in the browser? For example, it might be a .mp4 file or a .wav file.


Hi !
Thank you very much for your answer !
The preview doesn’t work only for video (mp4, mov…)

For the /etc/nginx/nginx.conf:

user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
        worker_connections 768;
        # multi_accept on;

http {

        # Basic Settings

        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 65;
        types_hash_max_size 204800;
        # server_tokens off;

        # server_names_hash_bucket_size 64;
        # server_name_in_redirect off;

        include /etc/nginx/mime.types;
        default_type application/octet-stream;

        # SSL Settings

        ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3; # Dropping SSLv3, ref: POODLE
        ssl_prefer_server_ciphers on;

        # Logging Settings

        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;

        # Gzip Settings

        gzip on;

        # gzip_vary on;
        # gzip_proxied any;
        # gzip_comp_level 6;
        # gzip_buffers 16 8k;
        # gzip_http_version 1.1;
        # gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

        # Virtual Host Configs

        include /etc/nginx/conf.d/*.conf;
        include /etc/nginx/sites-enabled/*;

And for the /etc/nginx/mime.types:

types {
    text/html                             html htm shtml;
    text/css                              css;
    text/xml                              xml;
    image/gif                             gif;
    image/jpeg                            jpeg jpg;
    application/javascript                js;
    application/atom+xml                  atom;
    application/rss+xml                   rss;

    text/mathml                           mml;
    text/plain                            txt;
    text/vnd.sun.j2me.app-descriptor      jad;
    text/vnd.wap.wml                      wml;
    text/x-component                      htc;

    image/png                             png;
    image/tiff                            tif tiff;
    image/vnd.wap.wbmp                    wbmp;
    image/x-icon                          ico;
    image/x-jng                           jng;
    image/x-ms-bmp                        bmp;
    image/svg+xml                         svg svgz;
    image/webp                            webp;

    application/font-woff                 woff;
    application/java-archive              jar war ear;
    application/json                      json;
    application/mac-binhex40              hqx;
    application/msword                    doc;
    application/pdf                       pdf;
    application/postscript                ps eps ai;
    application/rtf                       rtf;
    application/vnd.apple.mpegurl         m3u8;
    application/vnd.ms-excel              xls;
    application/vnd.ms-fontobject         eot;
    application/vnd.ms-powerpoint         ppt;
    application/vnd.wap.wmlc              wmlc;
    application/vnd.google-earth.kml+xml  kml;
    application/vnd.google-earth.kmz      kmz;
    application/x-7z-compressed           7z;
    application/x-cocoa                   cco;
    application/x-java-archive-diff       jardiff;
    application/x-java-jnlp-file          jnlp;
    application/x-makeself                run;
    application/x-perl                    pl pm;
    application/x-pilot                   prc pdb;
    application/x-rar-compressed          rar;
    application/x-redhat-package-manager  rpm;
    application/x-sea                     sea;
    application/x-shockwave-flash         swf;
    application/x-stuffit                 sit;
    application/x-tcl                     tcl tk;
    application/x-x509-ca-cert            der pem crt;
    application/x-xpinstall               xpi;
    application/xhtml+xml                 xhtml;
    application/xspf+xml                  xspf;
    application/zip                       zip;

    application/octet-stream              bin exe dll;
    application/octet-stream              deb;
    application/octet-stream              dmg;
    application/octet-stream              iso img;
    application/octet-stream              msi msp msm;
    application/vnd.openxmlformats-officedocument.wordprocessingml.document    docx;
    application/vnd.openxmlformats-officedocument.spreadsheetml.sheet          xlsx;
    application/vnd.openxmlformats-officedocument.presentationml.presentation  pptx;

    audio/midi                            mid midi kar;
    audio/mpeg                            mp3;
    audio/ogg                             ogg;
    audio/x-m4a                           m4a;
    audio/x-realaudio                     ra;

    video/3gpp                            3gpp 3gp;
    video/mp2t                            ts;
    video/mp4                             mp4;
    video/mpeg                            mpeg mpg;
    video/quicktime                       mov;
    video/webm                            webm;
    video/x-flv                           flv;
    video/x-m4v                           m4v;
    video/x-mng                           mng;
    video/x-ms-asf                        asx asf;
    video/x-ms-wmv                        wmv;
    video/x-msvideo                       avi;

I've never touched to those two files...
1 Like

Alright, so this is the live (the quoted line above) that needs to be changed. This is telling the server that by default, if it doesn’t recognize a specific file extension, or it isn’t specified in mime.types then it should download it to the user’s computer. By changing this line to default_type text/html;, and then restarting your Nginx server (sudo systemctl restart nginx) as well as restarting your Mattermost instance (sudo systemctl restart mattermost) you should be good to go!

Let me know how it goes and if it doesn’t work or you encounter any other issues, I’ll be more than happy to help out!


Thank you very much !
It worked !

1 Like

More than that, I can also see the whole pdf now (before I could only see 5 pages)

1 Like

That’s great, I’m very happy to hear that!