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58 lines
1.6 KiB
Markdown
58 lines
1.6 KiB
Markdown
# Fetch Data
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## Concepts
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- Like browsers, Deno implements web standard APIs such as
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[fetch](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API).
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- Deno is secure by default, meaning explicit permission must be granted to
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access the network
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- See also: Deno's [permissions](../getting_started/permissions.md) model
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## Overview
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When building any sort of web application developers will usually need to
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retrieve data from somewhere else on the web. This works no differently in Deno
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than in any other JavaScript application, just call the the `fetch()` method.
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For more information on fetch read the
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[MDN documentation](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API).
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The exception with Deno occurs when running a script which makes a call over the
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web. Deno is secure by default which means access to IO (Input / Output) is
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prohibited. To make a call over the web Deno must be explicitly told it is ok to
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do so. This is achieved by adding the `--allow-net` flag to the `deno run`
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command.
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## Example
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**Command:** `deno run --allow-net fetch.ts`
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```js
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/**
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* Output: JSON Data
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*/
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const json = fetch("https://api.github.com/users/denoland");
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json.then((response) => {
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return response.json();
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}).then((jsonData) => {
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console.log(jsonData);
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});
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/**
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* Output: HTML Data
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*/
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const text = fetch("https://deno.land/");
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text.then((response) => {
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return response.text();
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}).then((textData) => {
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console.log(textData);
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});
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/**
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* Output: Error Message
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*/
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const error = fetch("https://does.not.exist/");
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error.catch((error) => console.log(error.message));
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```
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