get-uri
v6.0.3
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Returns a `stream.Readable` from a URI string
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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 retreived 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
- Astream.Readable
instance from a previous call togetUri()
with the same URI. If this option is passed in, and the destination endpoint has not been modified, then anENOTMODIFIED
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
.