Background

I am a College Student and have been using and experimenting with Rust for a while now. I wrote a small crate to identify the various video formats using their magic bytes as kinda a project for getting selected in GSOC21. Sadly, it didn't work out but I thought now that I have the crate, I might as well publish it. I remember searching for it a year ago when I was trying to create a Plex like media server in Rust and coming up empty. So, I started looking at the Crates.io documentation and found it to be quite a painless process.

Introduction to Crate

The crate I wanted to publish was media_infer. It basically reads the starting bytes of a file or stream of bytes and tries to figure out the video container. The resources for the various magic bytes I used are given below:

• Wikipedia
• Garykessler

Steps to Publish

Create an account in Crates.io

Acquire API Token

You will need to create a new token the first time. It seems every device should have a different token. After the token is created, the Crates.io token section gives the command to type and it is something like this:

$ cargo login <token>

Add Metadata to the Cargo.toml

Set the fields like:

• authors
• license or license-file
• description
• homepage
• documentation
• repository
• readme
• keywords
• categoriesThe versioning should be kept in mind since there is no way to edit an already published crate.## Check LICENSE and README filesREADME file from the git repository is used and should be in markdown. Crates.io doesn't seem to recognize Org documents.## Check PackageThe files that will be included in teh .crate file can be checked using:

$ cargo package --list

Cargo will automatically ignore files ignored by your version control system when packaging, but if you want to specify an extra set of files to ignore you can use the exclude key in the manifest:

[package]# ...exclude = [    "public/assets/*",    "videos/*",]

Or include:

[package]# ...exclude = [    "public/assets/*",    "videos/*",]

Crates.io currently has a 10MB size limit on the .crate file.

Dry Run

Cargo has a pretty nifty command which basically checks if everything is in order and even gives warnings about things that can be improved.

$ cargo publish --dry-run

Publish

Once everything is finalized, the crate can be published using the simple command.

$ cargo publish

Once a version is already published, the same version cannot be published again even if the previous publish has been yanked.

Conclusion

This was the fist time I have published a library for any language, so it was kind of a great learning experience to actually do it myself. Earlier even though I knew what the crates were, it used to seem kind of like a difficult goal to achieve. Now, I think I understand and appreciate the crates a lot more.

Resources

• Crates.io Publish Guide
• Crates.io media_infer
• Github media_infer