Recurse Center 20: Parsing is hard. Let's go shopping.

So I've found that the pem crate I've been using doesn't parse headers, which are present in encrypted dsa private key files, and the mailparse crate doesn't parse properly with unix newlines, which seems to be what openssh generates even though in theory the RFCs involved require carriage return newline AFAIK.

So I spent most of the day writing my own PEM parser that handles headers and thinking about the things rust programmers think about:

• Can this be done without allocating any extra memory?
• Have I failed at life if I have to copy this 10-byte string before freeing it 4 nanoseconds later?
• Can I represent all of my data as a giant enum so rust models it as a single u64 bitfield or something?

You know, that kind of stuff.

But after another shopping spree on crates dot io I'm leaning heavily toward learning to use the nom crate to parse this. There's even an open github issue asking for an example DER private key parser, which is what I've been working on. However, the untrusted crate also looks promising. Tomorrow I'll see how quickly I can get something easy done with nom.

I also gave a talk on Serverless today and pointed out my hexagonal-lambda sample project.

Here's the unix tip of the day. If you have some utf8 characters encoded as hexadecimal you can convert to regular utf8 like this:

echo 65636473612d736861322d6e69737470333834 | xxd -r -p

Which prints ecdsa-sha2-nistp384