Environment Variables¶

The server can be configured via the following environment variables.

SERVER_HOST¶

The address of the host (e.g. 127.0.0.1). Default [::].

SERVER_PORT¶

The port of the host. Default 80.

SERVER_LISTEN_FD¶

Optional file descriptor number (e.g. 0) to inherit an already-opened TCP listener (instead of using SERVER_HOST and/or SERVER_PORT). Default empty (disabled).

SERVER_ROOT¶

Relative or absolute root directory path of static files. Default ./public.

SERVER_CONFIG_FILE¶

The Server configuration file path is in TOML format. See The TOML Configuration File.

SERVER_GRACE_PERIOD¶

Defines a grace period in seconds after a SIGTERM signal is caught which will delay the server before shutting it down gracefully. The maximum value is 255 seconds. The default value is 0 (no delay).

SERVER_LOG_LEVEL¶

Specify a logging level in lowercase. Possible values are error, warn, info, debug or trace. Default error.

SERVER_LOG_REMOTE_ADDRESS¶

Log incoming request information along with its Remote Address (IP) if available using the info log level. Default false.

SERVER_ERROR_PAGE_404¶

HTML file path for 404 errors. If the path is not specified or simply doesn't exist then the server will use a generic HTML error message. If a relative path is used then it will be resolved under the root directory. Default ./404.html.

SERVER_ERROR_PAGE_50X¶

HTML file path for 50x errors. If the path is not specified or simply doesn't exist then the server will use a generic HTML error message. If a relative path is used then it will be resolved under the root directory. Default ./50x.html

SERVER_FALLBACK_PAGE¶

HTML file path that is used for GET requests when the requested path doesn't exist. The fallback page is served with a 200 status code, useful when using client routers (e.g. `React Router``). If the path is not specified or simply doesn't exist then this feature will not be active.

SERVER_THREADS_MULTIPLIER¶

The number of worker threads multiplier will be multiplied by the number of system CPUs using the formula: worker threads = number of CPUs * n where n is the value that changes here. When the multiplier value is 0 or 1 then the number of CPUs is used. The number of worker threads result should be a number between 1 and 32,768 though it is advised to keep this value on the smaller side. Default one thread per core.

SERVER_MAX_BLOCKING_THREADS¶

Maximum number of blocking threads.

SERVER_HTTP2_TLS¶

Enable HTTP/2 with TLS support. Make sure also to adjust the current server port. Default false (disabled).

SERVER_HTTP2_TLS_CERT¶

Specify the file path to read the certificate. Default empty (disabled).

SERVER_HTTP2_TLS_KEY¶

Specify the file path to read the private key. Default empty (disabled).

SERVER_HTTPS_REDIRECT¶

Redirect all requests with scheme "http" to "https" for the current server instance. It depends on "http2" to be enabled.

SERVER_HTTPS_REDIRECT_HOST¶

Canonical hostname or IP of the HTTPS (HTTPS/2) server. It depends on "https-redirect" to be enabled. Default localhost.

SERVER_HTTPS_REDIRECT_FROM_PORT¶

HTTP host port where the redirect server will listen for requests to redirect them to HTTPS. It depends on "https-redirect" to be enabled. Default 80.

SERVER_HTTPS_REDIRECT_FROM_HOSTS¶

List of host names or IPs allowed to redirect from. HTTP requests must contain the HTTP 'Host' header and match against this list. It depends on "https-redirect" to be enabled. Default localhost.

SERVER_CORS_ALLOW_ORIGINS¶

Specify an optional CORS list of allowed origin hosts separated by commas. Host ports or protocols aren't being checked. Use an asterisk (*) to allow any host. Default empty (disabled).

SERVER_CORS_ALLOW_HEADERS¶

Specify an optional CORS list of allowed HTTP headers separated by commas. It requires SERVER_CORS_ALLOW_ORIGINS to be used along with. Default origin, content-type.

SERVER_CORS_EXPOSE_HEADERS¶

Specify an optional CORS list of exposed HTTP headers separated by commas. It requires SERVER_CORS_ALLOW_ORIGINS to be used along with. Default origin, content-type.

SERVER_COMPRESSION¶

Gzip, Deflate, Brotli or zlib compression on demand determined by the Accept-Encoding header and applied to text-based web file types only. See ad-hoc mime-type list. Default true (enabled).

SERVER_COMPRESSION_LEVEL¶

Supported values are fastest (fast compression but larger resulting files), best (smallest file size but potentially slow) and default (algorithm-specific balanced compression level). Default is default.

SERVER_COMPRESSION_STATIC¶

Look up the pre-compressed file variant (.gz, .br or .zst) on the disk of a requested file and serve it directly if available. Default false (disabled). The compression type is determined by the Accept-Encoding header.

SERVER_DIRECTORY_LISTING¶

Enable directory listing for all requests ending with the slash character (‘/’). Default false (disabled).

SERVER_DIRECTORY_LISTING_ORDER¶

Specify a default code number to order directory listing entries per Name, Last modified or Size attributes (columns). Code numbers supported: 0 (Name asc), 1 (Name desc), 2 (Last modified asc), 3 (Last modified desc), 4 (Size asc), 5 (Size desc). Default 6 (unordered).

SERVER_DIRECTORY_LISTING_FORMAT¶

Specify a content format for the directory listing entries. Formats supported: html or json. Default html.

SERVER_SECURITY_HEADERS¶

Enable security headers by default when the HTTP/2 feature is activated. Headers included: Strict-Transport-Security: max-age=63072000; includeSubDomains; preload (2 years max-age), X-Frame-Options: DENY and Content-Security-Policy: frame-ancestors 'self'. Default false (disabled).

SERVER_CACHE_CONTROL_HEADERS¶

Enable cache control headers for incoming requests based on a set of file types. The file type list can be found in src/control_headers.rs file. Default true (enabled).

SERVER_BASIC_AUTH¶

It provides The "Basic" HTTP Authentication Scheme using credentials as user-id:password pairs, encoded using Base64. Password must be encoded using the BCrypt password-hashing function. Default empty (disabled).

SERVER_REDIRECT_TRAILING_SLASH¶

Check for a trailing slash in the requested directory URI and redirect permanent (308) to the same path with a trailing slash suffix if it is missing. Default true (enabled).

SERVER_IGNORE_HIDDEN_FILES¶

Ignore hidden files/directories (dotfiles), preventing them from being served and being included in auto HTML index pages (directory listing).

SERVER_DISABLE_SYMLINKS¶

Prevent following files or directories if any path name component is a symbolic link.

SERVER_HEALTH¶

Activate the health endpoint.

SERVER_INDEX_FILES¶

List of files that will be used as an index for requests ending with the slash character (‘/’). Files are checked in the specified order. Default index.html.

SERVER_MAINTENANCE_MODE¶

Enable the server's maintenance mode functionality.

SERVER_MAINTENANCE_MODE_STATUS¶

Provide a custom HTTP status code when entering into maintenance mode. Default 503.

SERVER_MAINTENANCE_MODE_FILE¶

Provide a custom maintenance mode HTML file. If not provided then a generic message will be displayed.

Windows¶

The following options and commands are Windows platform-specific.

SERVER_WINDOWS_SERVICE¶

Run the web server in a Windows Service context. See more details.