num-client
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    2.0.2 • Public • Published

    NUM Client

    A TypeScript/JavaScript client for the NUM protocol.

    See the full Specification at the NUM Protocol Website and the Explainer for more information.

    The NUM protocol supports a range of modules that add rich functionality in an extensible way.

    The NUM URI Scheme

    The NUM protocol uses the familiar URL format for its URIs and allows modules to interpret data in a variety of ways.

    The data stored in a NUM Record is converted to JSON String format that can be parsed into JSON objects for straightforward incorporation into TypeScript and JavaScript programs. Here are some example NUM URIs with module 1 - the Contacts module. The default module is 0 (zero) if no module is specified, which has no module schema.

    • num://numexample.com:1
    • num://jo.smith@numexample.com:1
    • num://jo.smith@numexample.com:1/work
    • num://jo.smith@numexample.com:1/personal
    • num://jo.smith@numexample.com:1/hobbies
    • num://numexample.com:1/support
    • num://numexample.com:1/support/website
    • num://numexample.com:1/support/delivery
    • num://numexample.com:1/enquiries
    • num://numexample.com:1/sales

    As you can see from the examples above, data can be associated with domains and email addresses, and can be organised hierarchically if desired. In future, the protocol will support more than just domains and email addresses.

    Additional modules can be referenced in the same way as ports in other URIs:

    • num://numexample.com:2 for the Registrant module.
    • num://numexample.com:3 for the Images module.
    • num://numexample.com:4 for the Custodians module.
    • num://numexample.com:5 for the Payments module.
    • num://numexample.com:6 for the Regulatory module.
    • num://numexample.com:7 for the Public Key module.
    • num://numexample.com:8 for the Intellectual Property module.
    • num://numexample.com:9 for the Terms module.
    • num://numexample.com:10 for the Bugs module.
    • num://numexample.com:nn for your own module?

    Adding Support for the NUM Protocol

    Install using:

    npm install -s num-client

    TypeScript Examples

    Importing the Client

    Use this import to make the client available for use:

    import {
      createClient,     // required for creating the `NUMClient`
      createDnsClient,  // optional unless you need to override the default DoH endpoint
      parseNumUri,      // required for converting the NUM URI string into a valid `NumUri` object
      CallbackHandler,  // optional unless you need to provide a custom callback handler implementation
      DoHResolver,      // optional unless you need to override the default DoH endpoint
      Location          // optional unless you need to provide a custom callback handler implementation
    } from 'num-client';

    The Simplest Usage

    The programming interface is very simple:

    const lookup = async () => {
      const numUri = parseNumUri('num.uk:1');             // Parse the NUM URI
      const client = createClient();                      // Create a NumClient
      const ctx = client.createContext(numUri);           // Set the lookup context
      ctx.setTargetExpandedSchemaVersion('2');            // Set the required expanded schema version (specific to each module but defaults to 1)
      const result = await client.retrieveNumRecord(ctx); // Use the context to retrieve a NUM record
      console.log(result);                                // Handle the result
    }

    Reusing the NUMClient

    The same NUMClient can be reused for multiple lookups, as in this example:

    const lookup = async () => {
      const numUri1 = parseNumUri('num.uk:1');
      const numUri2 = parseNumUri('numexample.com:1');
    
      const client = createClient();            // This client is reused for multiple contexts
    
      const ctx1 = client.createContext(numUri1);
      const ctx2 = client.createContext(numUri2);
      ctx1.setTargetExpandedSchemaVersion('2');            // Set the required expanded schema version (specific to each module but defaults to 1)
      ctx2.setTargetExpandedSchemaVersion('2');            // Set the required expanded schema version (specific to each module but defaults to 1)
    
      const result1 = client.retrieveNumRecord(ctx1);
      const result2 = client.retrieveNumRecord(ctx2);
    
      const result = await Promise.all([result1, result2]);
    
      console.log(result[0]);
      console.log(result[1]);
    }

    Overriding the Default DoH Endpoint

    By default the NUMClient uses the Cloudflare and Google DoH resolvers, although it can be changed if required by providing a DoHResolver to a service that supports the JSON API for DNS over HTTPS (DoH).:

    const lookup = async () => {
      // ...
      const DEFAULT_RESOLVERS = [
        new DoHResolver('Cloudflare', 'https://cloudflare-dns.com/dns-query'),
        new DoHResolver('Quad9', 'https://dns10.quad9.net:5053/dns-query'),
      ];
    
      const client = createClient(DEFAULT_RESOLVERS); // Use a custom DoH service
      // ...
    };

    Providing User Variable Values

    Some modules can be provided with User Variable values to customise the output, as in this example:

    const lookup = async () => {
      const numUri = parseNumUri('num.uk:1');             // Parse the NUM URI
      const client = createClient();                      // Create a NumClient
      const ctx = client.createContext(numUri);           // Set the lookup context
      ctx.setTargetExpandedSchemaVersion('2');            // Set the required expanded schema version (specific to each module but defaults to 1)
    
      ctx.setUserVariable('_L', 'en');                    // Set the user's language
      ctx.setUserVariable('_C', 'gb');                    // Set the user's country
    
      const result = await client.retrieveNumRecord(ctx); // Use the context to retrieve a NUM record
      console.log(result)                                 // Handle the result
    }

    Using a CallbackHandler

    Lookups can take several seconds, so you can provide a CallbackHandler rather than awaiting the results:

    const lookup = async () => {
      const numUri = parseNumUri('num.uk:1');             // Parse the NUM URI
      const client = createClient();                      // Create a NumClient
      const ctx = client.createContext(numUri);           // Set the lookup context
      ctx.setTargetExpandedSchemaVersion('2');            // Set the required expanded schema version (specific to each module but defaults to 1)
    
      const handler: CallbackHandler = {
        setLocation: (l: NumLocation): void => {
          console.log(l); // `l` is the `Location` where the result was found
        },
        setResult: (r: string): void => {
          console.log(r); // `r` is the NUM record as a JSON string
        },
        setErrorCode: (e: string): void => {
          console.log(e); // `e` is the error message
        }
      };
    
      client.retrieveNumRecord(ctx, handler).then((_r) => {
        // Ignore because the callback handler will handle it
      }, (err) => console.error(err));
    }

    JavaScript Examples

    The Simplest Usage

    This example shows the minimal requirements for using the NUM Client:

    const num = require('num-client');
    
    num.lookup('num.uk:1').then((result) => console.log(result));

    Full Usage

    This example shows how to use all features of the client, including

    • overriding the DoH resolver,
    • reusing the NUMClient
    • setting user variables
    • using a callback handler
    const num = require('num-client');
    
    function lookup(uri1, uri2) {
      const numUri1 = num.parseNumUri(uri1);
      const numUri2 = num.parseNumUri(uri2);
    
      const DEFAULT_RESOLVERS = [
        new DoHResolver('Cloudflare', 'https://cloudflare-dns.com/dns-query'),
        new DoHResolver('Quad9', 'https://dns10.quad9.net:5053/dns-query'),
      ];
    
      const client = num.createClient(DEFAULT_RESOLVERS);
    
      const ctx1 = client.createContext(numUri1);
      const ctx2 = client.createContext(numUri2);
      ctx1.setTargetExpandedSchemaVersion('2');            // Set the required expanded schema version (specific to each module but defaults to 1)
      ctx2.setTargetExpandedSchemaVersion('2');            // Set the required expanded schema version (specific to each module but defaults to 1)
    
      ctx1.setUserVariable('_L', 'en');                    // Set the user's language
      ctx1.setUserVariable('_C', 'gb');                    // Set the user's country
    
      ctx2.setUserVariable('_L', 'en');                    // Set the user's language
      ctx2.setUserVariable('_C', 'us');                    // Set the user's country
    
      const handler = {                                    // Provide a custom CallbackHandler
        setLocation: (l) => {
          console.log(l);                                  // `l` is the `Location` where the result was found
        },
        setResult: (r) => {
          console.log(r);                                 // `r` is the NUM record as a JSON string
        },
        setErrorCode: (e) => {
          console.log(JSON.stringify(e));
        }
      };
    
      const result1 = client.retrieveNumRecord(ctx1, handler);
      const result2 = client.retrieveNumRecord(ctx2, handler);
    
      return Promise.all([result1, result2]);
    }
    
    lookup('num.uk:1', 'numexample.com:1').then((result) => {
      // Ignore because the callback handler will handle the results.
    });

    HTML and JavaScript Example

    The Simplest Usage

    This simple example can be modified as necessary by following the previous examples above.

    <!DOCTYPE html>
    <html lang="en">
    
    <head>
      <meta charset="utf-8" />
      <title>NUM Protocol Example</title>
    </head>
    
    <body>
      <script src="../dist/bundle.js"></script>
      <h1>NUM Protocol Example</h1>
      <div>
        NUM URI = <input type="text" value="num.uk:1" id='urivalue' onchange="reloadRecord()">
        <input type="button" value="Reload" onclick="reloadRecord()">
      </div>
      <div style="border: 1px solid blue;width: fit-content;">
        <pre id='num'></pre>
      </div>
      <script>
    
        const CUSTOM_RESOLVERS = [
          new NumClient.DoHResolver('Cloudflare', 'https://cloudflare-dns.com/dns-query')
        ];
    
        const client = NumClient.createClient(CUSTOM_RESOLVERS);
    
    
        function lookup(uri) {
          const numUri = NumClient.parseNumUri(uri);
    
          const ctx = client.createContext(numUri);
          if(numUri.port.n === 1 ) {
            ctx.setTargetExpandedSchemaVersion('2');
          }
    
          return client.retrieveNumRecord(ctx);
        }
    
        function reloadRecord() {
          const uri = document.getElementById('urivalue').value;
          lookup(uri).then((result) => {
            const pretty = JSON.stringify(JSON.parse(result), null, 1);
            document.getElementById('num').innerHTML = pretty;
          });
    
        }
    
        window.addEventListener('load', function () {
          reloadRecord();
        });
    
      </script>
    </body>
    
    </html>

    Keywords

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    Install

    npm i num-client

    DownloadsWeekly Downloads

    331

    Version

    2.0.2

    License

    Apache-2.0

    Unpacked Size

    547 kB

    Total Files

    59

    Last publish

    Collaborators

    • twalmsley