maghoff/include-dir-macro

A rust trait to include the source of all files in a given subdirectory in the generated binary, and make them available by path name through a hashmap.

include-dir-macro

Quick start:

Using a nightly toolchain, add this to your Cargo.toml:

[dependencies]
include-dir-macro = "0.1"

Then at the root of your crate (in main.rs or lib.rs), add the following:

#[feature(proc_macro)]
extern crate include-dir-macro;

Finally, you can call the macro as:

include_dir("path/to/directory");

If the path is a relative path, it will be interpreted relative to the directory from which cargo or rustc was invoked

Description

Provides an include_dir!() macro, which returns a HashMap<PathBuf, &'static [u8]> mapping files within a given directory to the contents of the file, stored within the built executable as static byte arrays. Given a crate with a directory structure like this:

/root
+-Cargo.toml
+-src/
| \-main.rs
|   
|       #[feature(proc_macro)]
|       extern crate include_dir_macro;
|       fn main() { 
|           let stat = include_dir!("static");
|       }
|   
\-static/
  +-this
  |
  |     ABC
  |
  +-that.html
  |
  |     <p>123</p>
  |
  \-path/
    \-to/
      \-theother.txt

            Do 
            re
            mi.

The value of stat will be the same as if main.rs included:

use std::collections::HashMap;
use std::path::PathBuf

fn main() {
    let stat = HashMap::new()
    stat.insert(PathBuf::from("this"), b"ABC\n");
    stat.insert(PathBuf::from("that.html"), b"<p>123</p>\n");
    stat.insert(PathBuf::from("path/to/theother.txt"), b"Do\nre\nmi.\n");
}

Rationale

Out of the box, Rust provides a macro called include_bytes!(), which loads the contents of a file into a static byte array at compile time. The contents then live in the binary, requiring no further access to the filesystem. I thought this could be useful for bundling up entire directories, to provide a way to make, for example, whole websites bundled as a static binary, containing all associated images, stylesheets, and scripts.

One shortcoming of of include_bytes!() for this use case is that it only operates on paths specified as str literals, so to use it for an entire directory, one would have to add each file by hand. I saw two ways around this:

One is to include code-generation in a crate's build.rs script that crawls the included directory, and adds an include_str for each file. This method is supported by another crate called "include_dir", but I wanted an approach with the ergonomic simplicity of the include_bytes!() macro. This required using procedural macros, which in turn means that it currently (as of Rust 1.21) rustonly works on nightly releases.