static-web-server.git

# Environment Variables

The server can be configured via the following environment variables.

!!! tip "Remember"
    - Environment variables are equivalent to their command-line arguments.
    - [Command-line arguments](./command-line-arguments.md) take precedence over their equivalent 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 on (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](../configuration/config-file.md).

### 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 lower case. Possible values are `error`, `warn`, `info`, `debug` or `trace`. Default `error`.

### SERVER_LOG_REMOTE_ADDRESS
Log incoming requests 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 that'll 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` or `Brotli` compression on demand determined by the `Accept-Encoding` header and applied to text-based web file types only. See [ad-hoc mime-type list](https://github.com/static-web-server/static-web-server/blob/master/src/compression.rs#L20). Default `true` (enabled).

### SERVER_COMPRESSION_STATIC
Look up the pre-compressed file variant (`.gz` or `.br`) on disk of a requested file and serves 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 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 on [`src/control_headers.rs`](https://github.com/static-web-server/static-web-server/blob/master//src/control_headers.rs) file. Default `true` (enabled).

### SERVER_BASIC_AUTH
It provides [The "Basic" HTTP Authentication Scheme](https://datatracker.ietf.org/doc/html/rfc7617) using credentials as `user-id:password` pairs, encoded using `Base64`. Password must be encoded using the [BCrypt](https://en.wikipedia.org/wiki/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 to be served and being included in auto HTML index pages (directory listing).

### 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](../features/windows-service.md).