get-uri

Returns a stream.Readable from a URI string

This high-level module accepts a URI string and returns a Readable stream instance. There is built-in support for a variety of "protocols", and it's easily extensible with more:

Protocol	Description	Example
data	Data URIs	data:text/plain;base64,SGVsbG8sIFdvcmxkIQ%3D%3D
file	File URIs	file:///c:/windows/example.ini
ftp	FTP URIs	ftp://ftp.kernel.org/pub/site/README
http	HTTP URIs	http://www.example.com/path/to/name
https	HTTPS URIs	https://www.example.com/path/to/name

Example

To simply get a stream.Readable instance from a file: URI, try something like:

import { getUri } from 'get-uri';

// `file:` maps to a `fs.ReadStream` instance…
const stream = await getUri('file:///Users/nrajlich/wat.json');
stream.pipe(process.stdout);

Missing Endpoints

When you pass in a URI in which the resource referenced does not exist on the destination server, then a NotFoundError will be thrown. The code of the error instance is set to "ENOTFOUND", so you can check for that value to detect when a bad filename is requested:

try {
  await getUri('http://example.com/resource.json');
} catch (err) {
  if (err.code === 'ENOTFOUND') {
    // bad file path requested
  } else {
    // something else bad happened...
    throw err;
  }
}

Cacheability

When calling getUri() with the same URI multiple times, the get-uri module supports sending an indicator that the remote resource has not been modified since the last time it has been retrieved from that node process.

To do this, define a cache property on the "options object" argument with the value set to the stream.Readable instance that was previously returned. If the remote resource has not been changed since the last call for that same URI, then a NotModifiedError instance will be thrown with its code property set to "ENOTMODIFIED".

When the "ENOTMODIFIED" error occurs, then you can safely re-use the results from the previous getUri() call for that same URI:

// First time fetches for real
const stream = await getUri('http://example.com/resource.json');

try {
  // … some time later, if you need to get this same URI again, pass in the
  // previous `stream.Readable` instance as `cache` option to potentially
  // have an "ENOTMODIFIED" error thrown:
  await getUri('http://example.com/resource.json', { cache: stream });
} catch (err) {
  if (err.code === 'ENOTMODIFIED') {
    // source file has not been modified since last time it was requested,
    // so you are expected to re-use results from a previous call to `getUri()`
  } else {
    // something else bad happened...
    throw err;
  }
}

API

getUri(uri: string | URL, options?: Object]): Promise

A uri is required. An optional options object may be passed in:

• cache - A stream.Readable instance from a previous call to getUri() with the same URI. If this option is passed in, and the destination endpoint has not been modified, then an ENOTMODIFIED error is thrown

Any other options passed in to the options object will be passed through to the low-level connection creation functions (http.get(), ftp.connect(), etc).

Returns a stream.Readable instance to read the resource at the given uri.