FP-Signature

Fynd platform's signature logic

FP-Signature is a versatile npm package that provides signature logic for Fynd platform requests. This package supports both CommonJS and ES modules, and it also comes with a web bundle for direct usage in browsers.

Installation

You can install FP-Signature via npm:

npm install @gofynd/fp-signature

How to Use

For CommonJS

const { sign } = require("@gofynd/fp-signature");

For ES Modules

import { sign } from "@gofynd/fp-signature";

For Browser

<script src="https://cdn.jsdelivr.net/npm/@gofynd/fp-signature@{version}"></script>
<script>
    // FP-Signature library will be attached to the global window object
    FPSignature.sign();
</script>

In Postman Prescript

To use FP-Signature in Postman as a pre-script, include the postman_prescript.js file in the pre-script section of your Postman collection.

Change the FP-Signature package version within the pre-script according to your requirements.

Functionality

sign function

The sign function is used to generate a signature. It takes two parameters: request and options.

It will return Signature object with x-fp-date and x-fp-signature.

Include the generated x-fp-date and x-fp-signature in the request headers or query parameters to sign the request.

type RequestParam = {
  method: string;
  host?: string;
  port?: number;
  path?: string;
  headers?: any;
  body?: any;
  doNotEncodePath?: boolean;
  doNotModifyHeaders?: boolean; 
};

type SigningOptions = {
    secret?: string;
    signQuery?: boolean;
}

type Signature = {
    "x-fp-signature": string;
    "x-fp-date": string;
}

function sign(request : RequestParam, options: SigningOptions) : Signature {}

RequestParam Object

The RequestParam object is used to configure the details of the HTTP request that needs to be signed.

Properties:

• method: (string, required) - HTTP method for the request (e.g., "GET", "POST").

• host: (string, optional) - The host of the server. Ex: developer.mozilla.org:4097, api.fyndx5.de

• port: (number, optional) - The port number of the server.

• path: (string, optional) - The path of the request URL with query parameters(if any).

• headers: (object, optional) - Custom headers for the request. Exclude default headers like common, delete, get, head, post, put, patch.

• body: (any, optional) - The body of the request.

• doNotEncodePath: (boolean, optional) - If true, the path will not be URL encoded.

• doNotModifyHeaders: (boolean, optional) - If true, headers will not be modified during signing.

Example:

const requestToSign = {
    method: "GET",
    host: "api.fynd.com",
    path: "/service/application/configuration/v1.0/application?queryParam=value",
    headers: {
      Authorization: "Bearer <authorizationToken>",
      "x-currency-code": "INR"
    },
};

Signature Placement

The placement of the signature (x-fp-signature) in the request is determined by the options.signQuery property:

• If options.signQuery is true, the x-fp-signature will be generated to use in query parameter.
• If options.signQuery is false, the x-fp-signature will be generated to use in headers.

Example

Signature to add in header

// For Common JS
// const {sign} = require("@gofynd/fp-signature")

// For ES Module
import {sign} from "@gofynd/fp-signature";

const requestToSign = {
  method: "GET",
  host: "api.fynd.com",
  path: "/service/application/configuration/v1.0/application",
  headers: {
    Authorization: "Bearer <authorizationToken>",
    "x-currency-code": "INR"
  },
};

const signature = sign(requestToSign);

const res = axios.get("http://api.fynd.com/service/application/configuration/v1.0/application", {
  headers: {
    Authorization: "Bearer <authorizationToken>",
    "x-currency-code": "INR",
    "x-fp-signature": signature["x-fp-signature"],
    "x-fp-date": signature["x-fp-date"]
  }
});

Signature to add in query

// For Common JS
// const {sign} = require("@gofynd/fp-signature")

// For ES Module
import {sign} from "@gofynd/fp-signature";

const requestToSign = {
  method: "GET",
  host: "api.fynd.com",
  path: "/service/application/configuration/v1.0/application",
  headers: {
    Authorization: "Bearer <authorizationToken>",
    "x-currency-code": "INR"
  },
};

const signature = sign(requestToSign, {
  signQuery: true
});

const res = axios.get("http://api.fynd.com/service/application/configuration/v1.0/application", {
  params: {
    "x-fp-signature": signature["x-fp-signature"],
    "x-fp-date": signature["x-fp-date"]
  },
  headers: {
    Authorization: "Bearer <authorizationToken>",
    "x-currency-code": "INR"
  }
});