Step by Step Guide to Building a SignNow API Integration in JS

Introduction

Hey there, fellow developer! Ready to dive into the world of electronic signatures? Let's talk about integrating SignNow's API into your JavaScript project. With the @signnow/api-client package, you'll be up and running in no time. Trust me, it's easier than you think!

Prerequisites

Before we jump in, make sure you've got:

• Node.js and npm installed (you're a dev, so I'm sure you do!)
• A SignNow account with API credentials (if not, go grab one real quick)

Setting up the project

Let's get this show on the road:

mkdir signnow-integration
cd signnow-integration
npm init -y
npm install @signnow/api-client

Boom! You're ready to roll.

Authentication

First things first, let's get you authenticated:

const { SignNowClient } = require('@signnow/api-client');

const client = new SignNowClient({
  clientId: 'YOUR_CLIENT_ID',
  clientSecret: 'YOUR_CLIENT_SECRET'
});

async function authenticate() {
  try {
    await client.oauth2.requestToken();
    console.log('Authenticated successfully!');
  } catch (error) {
    console.error('Authentication failed:', error);
  }
}

authenticate();

Basic API operations

Now that we're in, let's do some cool stuff:

Create a document

async function createDocument() {
  try {
    const document = await client.document.create({
      file: fs.createReadStream('path/to/your/document.pdf')
    });
    console.log('Document created:', document.id);
    return document;
  } catch (error) {
    console.error('Failed to create document:', error);
  }
}

Add fields to a document

async function addFields(documentId) {
  try {
    await client.document.addFields(documentId, {
      fields: [
        {
          type: 'signature',
          x: 100,
          y: 100,
          width: 200,
          height: 50,
          page_number: 1
        }
      ]
    });
    console.log('Fields added successfully!');
  } catch (error) {
    console.error('Failed to add fields:', error);
  }
}

Send document for signing

async function sendForSigning(documentId, recipientEmail) {
  try {
    await client.document.invite(documentId, {
      to: [{ email: recipientEmail }],
      subject: 'Please sign this document',
      message: 'Your signature is required.'
    });
    console.log('Document sent for signing!');
  } catch (error) {
    console.error('Failed to send document:', error);
  }
}

Handling webhooks

Set up an endpoint to receive webhook notifications:

const express = require('express');
const app = express();

app.post('/webhook', express.json(), (req, res) => {
  const event = req.body;
  console.log('Received webhook:', event);
  // Process the event
  res.sendStatus(200);
});

app.listen(3000, () => console.log('Webhook server running on port 3000'));

Error handling and best practices

Always wrap your API calls in try-catch blocks, and don't forget about rate limiting:

const { RateLimiter } = require('limiter');
const limiter = new RateLimiter({ tokensPerInterval: 5, interval: 'second' });

async function rateLimitedApiCall(apiFunction) {
  await limiter.removeTokens(1);
  try {
    return await apiFunction();
  } catch (error) {
    console.error('API call failed:', error);
  }
}

Testing the integration

Don't forget to test! Here's a quick example using Jest:

const { SignNowClient } = require('@signnow/api-client');

jest.mock('@signnow/api-client');

test('createDocument creates a document', async () => {
  const mockCreate = jest.fn().mockResolvedValue({ id: '123' });
  SignNowClient.mockImplementation(() => ({
    document: { create: mockCreate }
  }));

  const result = await createDocument();
  expect(result.id).toBe('123');
  expect(mockCreate).toHaveBeenCalled();
});

Deployment considerations

When deploying, keep your API credentials safe:

• Use environment variables
• Implement proper access controls
• Consider using a secrets management service

Conclusion

And there you have it! You've just built a SignNow API integration in JS. Pretty cool, right? Remember, this is just scratching the surface. The SignNow API has tons more features to explore.

Keep coding, keep learning, and most importantly, keep having fun with it! If you need more info, check out the SignNow API docs. Happy integrating!