Twine

A command line Twitter client (CLI)

Project Directory Structure

• /bin: Options parsing, Help text, Command execution
• /commands: User input, Console output, Sequence of steps
• /lib: Store/load credentials, Make API calls, Utilities

Twine in Three Steps

• Consumer API Key and Secret
• Twitter Account Token and Secret
• Specific Twitter API Call

Handling Errors

Workflow: /bin --> /commands --> /lib Errors: /lib --> /commands --> /bin

Exiting Node.js Correctly on Error

// This is an example of what NOT to do:
if (someConditionNotMet()) {
    printUsageToStdout();
    process.exit(1);
}

// How to properly set the exit code while letting
// the process exit gracefully
if (someConditionNotMet()) {
    printUsageToStdout();
    process.exitCode = 1;
}

Environment Variables

• Consumer API Key and Secret:

  • TWINE_CONSUMER_KEY
  • TWINE_CONSUMER_SECRET

• Twitter Account Token and Secret:

  • TWINE_ACCOUNT_KEY
  • TWINE_ACCOUNT_SECRET

Setting Environment Variables

set TWINE_CONSUMER_KEY=key
set TWINE_CONSUMER_SECRET=secret

Note:

• Standard In: process.stdin
• Standard Out: process.stdout
• Standard Error: process.stderr

process.stdin.pipe(process.stdout)

Support params both on the command line and read from stdin

• A single parameter

twine [some command] param
echo "param" | twine [some command]

• Multiple parameters

twine [some command] param1, param2
twine [some command] < param-file.txt
param-generator | twine [some command]

Examples:

param-generator | twine lookup users

1. process.stdin
2. split on newline
3. batches of 100
4. Twitter API(s)
5. flatten
6. JSON stringify
7. process.stdout

twine lookup users user1,user2

1. CLI params
2. array
3. batches of 100
4. Twitter API(s)
5. flatten
6. JSON stringify
7. process.stdout

Several New Stream-related Modules

• split2
• parallel-transform
• through2
• JSONStream
• from2-array
• promise-streams

Example

users.txt

user1
user2

cmd

type users.txt | twine lookup users

JQ (find out more about this)

choco install jq

Publish our command line app!

Publishing to npm

Two simple commands:

• npm login
• npm publish

However we need a scoped package: @miguelleonmarti/twine (miguelleonmarti is the scope) Why using scoped packages in npm? Due to private packages, grouping, namespacing

Executing Binaries Directly with npx

• Typical module usage:

npm install -g @miguelleonmarti/twine
twine lookup users miguelleonmarti

• With npx:

npx @miguelleonmarti/twine lookup users miguelleonmarti

Automatically check for updates

Automate our deployments

Create a Docker image for our CLI