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@ideal-postcodes/core-interface

1.4.0 • Public • Published

Ideal Postcodes Core Interface

JavaScript API for api.ideal-postcodes.co.uk

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@ideal-postcodes/core-interface is an environment agnostic implementation of the Ideal Postcodes JavaScript API client interface.

If you are looking for the browser or Node.js client which implements this interface, please check out the downstream clients links.

Links

Downstream Clients

Documentation

Methods

Usage

To install, pick one of the following based on your platform

# For browser client 
npm install @ideal-postcodes/core-browser
 
# For node.js client 
npm install @ideal-postcodes/core-node
 
# For generic interface (you need to supply your own HTTP agent) 
npm install @ideal-postcodes/core-interface

Instantiate a client with

import { Client } from "@ideal-postcodes/core-<package-type>";
 
const client = new Client({ api_key: "iddqd" });
 
// Only api_key is required by core-node and core-browser - all others are optional
// The agentless interface requires explicit configuration

Configuration options


Quick Methods

The client exposes a number of simple methods to get at the most common tasks when interacting with the API

Lookup a Postcode

Return addresses associated with a given postcode

const postcode = "id11qd";
 
client.lookupPostcode({ postcode }).then(addresses => {
  console.log(addresses);
  {
    postcode: "ID1 1QD",
    line_1: "2 Barons Court Road",
    // ...etc...
  }
});

Method options

Search for an Address

Return addresses associated with a given query

const query = "10 downing street sw1a";
 
client.lookupAddress({ query }).then(addresses => {
  console.log(addresses);
  {
    postcode: "SW1A 2AA",
    line_1: "Prime Minister & First Lord Of The Treasury",
    // ...etc...
  }
});

Method options

Search for an Address by UDPRN

Return address for a given udprn

Invalid UDPRN will return null

const udprn = 23747771;
 
client.lookupUdprn({ udprn }).then(address => {
  console.log(address);
  {
    postcode: "SW1A 2AA",
    line_1: "Prime Minister & First Lord Of The Treasury",
    // ...etc...
  }
});

Method options

Search for an Address by UMPRN

Return address for a given umprn

Invalid UMPRN will return null

const umprn = 50906066;
 
client.lookupUmprn({ umprn }).then(address => {
  console.log(address);
  {
    postcode: "CV4 7AL",
    line_1: "Room 1, Block 1 Arthur Vick",
    // ...etc...
  }
});

Method options

Check Key Usability

Check if a key is currently usable

client.checkKeyUsability({}).then(key => {
  console.log(key.available); // => true
});

Method options


Resources

Resources defined in the API documentation are exposed on the client. Each resource exposes a method (#retrieve, #list, etc) which maps to a resource action.

These methods expose a low level interface to execute HTTP requests and observe HTTP responses. They are ideal if you have a more complex query or usecase where low level access would be useful.

Resource methods return a promise with a HTTP response object type.

Retrieve

Requesting a resource by ID (e.g. a postcode lookup for postcode with ID "SW1A 2AA") maps to the #retrieve method.

The first argument is the resource ID. The second argument is an object which accepts header and query attributes that map to HTTP header and the request querystring.

client.resourceName.retrieve("id", {
  query: {
    api_key: "foo",
    tags: "this,that,those",
    licensee: "sk_99dj3",
  },
  header: {
    "IDPC-Source-IP": "8.8.8.8",
  },
  timeout: 5000,
});

List

Requesting a resource endpoint (e.g. an address query to /addresses) maps to the #list method.

client.resourceName.list({
  query: {
    api_key: "foo",
    query: "10 downing street"
  },
  header: {
    "IDPC-Source-IP": "8.8.8.8",
  },
  timeout: 5000,
});

The first and only argument is an object which accepts header and query attributes that map to HTTP header and the request querystring.

Custom Actions

Some endpoints are defined as custom actions, e.g. /keys/:key/usage. These can be invoked using the name of the custom action.

E.g. for key usage data extraction

client.keys.usage(api_key, {
  query: {
    tags: "checkout,production"
  },
  header: {
    Authorization: 'IDEALPOSTCODES user_token="foo"',
  },
  timeout: 5000,
});

Resource Methods

Listed below are the available resources exposed by the client:

Postcodes

Retrieve addresses for a postcode.

client.postcodes.retrieve("SW1A2AA", {
  header: {
    "Authorization": 'IDEALPOSTCODES api_key="iddqd"',
  },
}).then(response => {
  const addresses = response.body.result;
}).catch(error => logger(error));

See postcode resource API documentation

Addresses

Search for an address

client.addresses.list({
  query: {
    query: "10 Downing street",
  },
  header: {
    "Authorization": 'IDEALPOSTCODES api_key="iddqd"',
  },
}).then(response => {
  const addresses = response.body.result.hits;
}).catch(error => logger(error));

See addresses resource API documentation

Autocomplete

Autocomplete an address given an address partial

client.autocomplete.list({
  query: {
    query: "10 Downing stre",
  },
  header: {
    "Authorization": 'IDEALPOSTCODES api_key="iddqd"',
  },
}).then(response => {
  const suggestions = response.body.result.hits;
}).catch(error => logger(error));

See autocomplete resource API documentation

UDPRN

Retrieve an address given a UDPRN

client.udprn.retrieve("12345678", {
  header: {
    "Authorization": 'IDEALPOSTCODES api_key="iddqd"',
  },
}).then(response => {
  const address = response.body.result;
}).catch(error => logger(error));

See UDPRN resource API documentation

UMPRN

Retrieve a multiple residence premise given a UMPRN

client.umprn.retrieve("87654321", {
  header: {
    "Authorization": 'IDEALPOSTCODES api_key="iddqd"',
  },
}).then(response => {
  const address = response.body.result;
}).catch(error => logger(error));

See UMPRN resource API documentation

Keys

Find out if a key is available

client.keys.retrieve("iddqd", {})
  .then(response => {
    const { available } = response.body.result;
  }).catch(error => logger(error));

Get private information on key (requires user_token)

client.keys.retrieve("iddqd", {
  header: {
    "Authorization": 'IDEALPOSTCODES user_token="secret-token"',
  },
}).then(response => {
  const key = response.body.result;
}).catch(error => logger(error));

Get key usage data

client.keys.usage("iddqd", {
  header: {
    "Authorization": 'IDEALPOSTCODES user_token="secret-token"',
  },
}).then(response => {
  const key = response.body.result;
}).catch(error => logger(error));

See Keys resource API documentation


Error Handling

Client exports a static variable errors which contains custom error constructors that wrap specific API errors. These constructors can be used to test for specific cases using the instanceof operator.

For example:

const { IdpcInvalidKeyError } = Client.errors;
 
try {
  const addresses = client.lookupPostcode({ postcode: "SW1A2AA" });
} catch (error) {
  if (error instanceof IdpcInvalidKeyError) {
    // Handle an invalid key error
  }
}

Not all specific API errors will be caught. If a specific API error does not have an error constructor defined, a more generic error (determined by the HTTP status code) will be returned.

For example:

const { IdpcRequestFailedError } = Client.errors;
 
try {
  const addresses = client.lookupPostcode({ postcode: "SW1A2AA" });
} catch (error) {
  if (error instanceof IdpcRequestFailedError) {
    // IdpcRequestFailedError indicates a 402 response code
    // Possibly the key balance has been depleted
  }
}

A sketch of the error prototype chain can be found here


Core Interface Errors

For more advanced use cases, this core-interface library provides:

  • Class implementations for Ideal Postcodes API errors that inherit from Error
  • A parser that converts raw error data into one of these error instances

Usage

Aside from inspecting the HTTP request status code and/or JSON body response codes, you may also test for specific error instances.

Errors that don't inherit from IdealPostcodesError would indicate some kind of error external to the API (e.g. bad network, request timeout).

import { errors } from "@ideal-postcodes/core-interface";
const { IdpcPostcodeNotFoundError } = errors;
 
// Handle a specific error
if (error instanceof IdpcPostcodeNotFoundError) {
  // You got yourself an invalid API Key
}
 
// Alternatively use a switch statement
switch (true) {
  case error instanceof IdpcPostcodeNotFoundError:
    // You got yourself an invalid API Key
  default:
    // Default error handling path
}

Error Prototype Chain

All errors inherit from JavaScript's Error prototype.

Errors are grouped by HTTP status code classes.

Specific errors may be supplied for the following reasons:

  • Convenience: They are frequently tested for (e.g. invalid postcode, postcode not found)
  • Developer QoL. They are useful for debug purposes during the implementation stages
Prototype Chain
 
# Parent class inherits from Javascript Error. Returned if no JSON Response body
IdealPostcodesError < Error
|
|- IdpcApiError # Generic Error Class, returned if JSON response body present
   |
   |- IdpcBadRequestError          # 400 Errors
   |- IdpcUnauthorisedError        # 401 Errors
   |- IdpcRequestFailedError       # 402 Errors
   |  |- IdpcBalanceDepletedError
   |  |- IdpcLimitReachedError
   |
   |- IdpcResourceNotFoundError    # 404 Errors
   |  |- IdpcPostcodeNotFoundError
   |  |- IdpcKeyNotFoundError
   |  |- IdpcUdprnNotFoundError
   |  |- IdpcUmprnNotFoundError
   |
   |- IdpcServerError              # 500 Errors

Error Parser

The error parser consumes a HTTP API response and returns the correct error instance.

import { errors } from "@ideal-postcodes/core-interface";
const { parse, IdpcPostcodeNotFoundError } = errors;
 
const invalidPostcodeUrl = "https://api.ideal-postcodes.co.uk/v1/postcodes/bad_postcode?api_key=iddqd"
 
const response = await fetch(invalidPostcodeUrl);
 
// Generate an error object if present, otherwise returns `undefined`
const error = parse(response);
 
// Handle the error
if (error instanceof IdpcPostcodeNotFoundError) {...}

Test

npm test

Licence

MIT

Install

npm i @ideal-postcodes/core-interface

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Version

1.4.0

License

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