Digikey API and OAuth

Posted On: July 31, 2016

OAuth is harder than expected. I’m just going to jot down some notes as I go:

node interpreter is very useful for quickly testing out packages! Just run “node” from the command line. “.exit” quits the interpreter.

A nice way to keep secrets in a node system is in a file, with good system permissions. If you make the file follow the JSON file format:

  "key": "value",
  "key_of_set": ["value1", "value2"],
  "key_of_dict": {"keys_forever": "values too"}


then running:

var file_json = require("path_to_file.json")

loads your object into file_json.

Versioning this secret file is fun. You can make a dummy file, with something like "secret_key": "mtwannahuckaloogie" git add that file, then put the file on a .gitignore and run:

git update-index --assume-unchanged 

and git will ignore it forevermore! (I think. Probably try not to shake your index too hard or you might leak it)

The usual package protocol:

npm install --save simple-oauth2

gets the app ready for action! (i hope)

The OAuth demo code on the npm page for simple-oauth2 is pretty straightforward, I basically copy pasted it, along with the relevant clientID and clientSecret given by digikey.
Unfortunately, my hope for having the callback address of work, was a bust. Looks like tomorrow I’ll need to do some funny business to open up some ports :O

Ok, the redirect isn’t accessed by Digikey, its simply stuffed into the user’s browser. This is good, I was just being an idiot on the config side at Digikey. When Digkey asked for my apps redirect callback URI, I gave it the user was then sent to their own port 3000, obviously wrong it should go to my webserve’s port 3000. for me on lan, that means 192.168.x.x:3000/callback. This works better, gets me to digikey’s login.

HOWEVER, Digikey wants an https address for the callback (doesn’t look required by oauth since the demo code uses http), so I guess I need to set up https for the app. Since I’m not paying the big bucks for getting a cert from a CA (though I could get one from MIT for the next year), I’ll just self-sign one. Instructions on that can be found at: https://github.com/nodejitsu/docs/blob/master/pages/articles/HTTP/servers/how-to-create-a-HTTPS-server/content.md

I’ll lay down the gist here though since that url seems unstable

openssl genrsa -out key.pem
openssl req -new -key key.pem -out csr.pem
openssl x509 -req -days 9999 -in csr.pem -signkey key.pem -out cert.pem
rm csr.pem

The package ‘https’ will automatically manage the remainder of the connection stuff. If you’ve used the express directory formatter/file autogen thing, then you’ll want to edit your /bin/www.


var https = require('https');
var fs = require('fs');

var https_config = {
  key: fs.readFileSync('key.pem'),
  cert: fs.readFileSync('cert.pem')

var https_server = https.createServer(https_config, app);


And replacing the port in listen() with the port you want. Make sure create_server goes after the var app = express(); line.

The https stuff was a problem, as Digikey won’t accept a redirect without ssl, but not the big problem. Even after getting that set up, I kept getting ERROR 402’s all the time. I had subscribed to the API’s using the kind of hidden buttons on the Digikey API page, and was flummoxed at what the problem was. “PAYMENT_REQUIRED”? Sometimes this error is used for APIs you have exceeded quotas on or need to pay for. Adding some console.logs to the simple-oauth library, I extracted the full reply from the server:

The client MUST NOT use more than one authentication method in each request.

Huh? I thought I was only using one… I dumped the POST request parameters just before they were sent (also by throwing a console.log into the library files) and noticed Authorization: Basic ... in there with a huge hash of some kind. Crap! There’s a default token of some kind coming from simple-oauth2, you just have to add

useBasicAuthorizationHeader: false

to the config parameters for simple-oauth2, and then you /just/ have the authentication code coming in. FIXED!

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