{"id":8997,"date":"2023-09-23T14:49:24","date_gmt":"2023-09-23T06:49:24","guid":{"rendered":"\/?p=8997"},"modified":"2023-09-23T14:49:24","modified_gmt":"2023-09-23T06:49:24","slug":"javascript%e4%bd%bf%e7%94%a8fetch%e7%9a%84%e6%96%b9%e6%b3%95%e8%af%a6%e8%a7%a3","status":"publish","type":"post","link":"\/?p=8997","title":{"rendered":"JavaScript\u4f7f\u7528Fetch\u7684\u65b9\u6cd5\u8be6\u89e3"},"content":{"rendered":"<h1>JavaScript\u4f7f\u7528Fetch\u7684\u65b9\u6cd5\u8be6\u89e3<\/h1>\n<p>FetchAPI\u63d0\u4f9b\u4e86\u4e00\u4e2aJavaScript\u63a5\u53e3\uff0c\u7528\u4e8e\u8bbf\u95ee\u548c\u64cd\u7eb5HTTP\u7ba1\u9053\u7684\u90e8\u5206\u3002\u5b83\u8fd8\u63d0\u4f9b\u4e86\u4e00\u4e2a\u5168\u5c40fetch()\u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u63d0\u4f9b\u4e86\u4e00\u79cd\u7b80\u5355\uff0c\u5408\u7406\u7684\u65b9\u5f0f\u6765\u8de8\u7f51\u7edc\u5f02\u6b65\u83b7\u53d6\u8d44\u6e90\u3002\u672c\u6587\u5c06\u8be6\u89e3JS\u5982\u4f55\u4f7f\u7528Fetch\uff0c\u611f\u5174\u8da3\u7684\u53ef\u4ee5\u5b66\u4e60\u4e00\u4e0b<\/p>\n<p><a href=\"https:\/\/developer.mozilla.org\/en-US\/docs\/Web\/API\/Fetch_API\">Fetch API<\/a> \u63d0\u4f9b\u4e86\u4e00\u4e2a JavaScript\u63a5\u53e3\uff0c\u7528\u4e8e\u8bbf\u95ee\u548c\u64cd\u7eb5HTTP\u7ba1\u9053\u7684\u90e8\u5206\uff0c\u4f8b\u5982\u8bf7\u6c42\u548c\u54cd\u5e94\u3002\u5b83\u8fd8\u63d0\u4f9b\u4e86\u4e00\u4e2a\u5168\u5c40 <code>fetch()<\/code>\u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u63d0\u4f9b\u4e86\u4e00\u79cd\u7b80\u5355\uff0c\u5408\u7406\u7684\u65b9\u5f0f\u6765\u8de8\u7f51\u7edc\u5f02\u6b65\u83b7\u53d6\u8d44\u6e90\u3002<\/p>\n<p>\u8fd9\u79cd\u529f\u80fd\u4ee5\u524d\u662f\u4f7f\u7528 <code>XMLHttpRequest<\/code>\u5b9e\u73b0\u7684\u3002Fetch\u63d0\u4f9b\u4e86\u4e00\u4e2a\u66f4\u597d\u7684\u66ff\u4ee3\u65b9\u6cd5\uff0c\u53ef\u4ee5\u5f88\u5bb9\u6613\u5730\u88ab\u5176\u4ed6\u6280\u672f\u4f7f\u7528\uff0c\u4f8b\u5982 <code>Service Workers<\/code>\u3002Fetch\u8fd8\u63d0\u4f9b\u4e86\u5355\u4e2a\u903b\u8f91\u4f4d\u7f6e\u6765\u5b9a\u4e49\u5176\u4ed6HTTP\u76f8\u5173\u6982\u5ff5\uff0c\u4f8b\u5982CORS\u548cHTTP\u7684\u6269\u5c55\u3002<\/p>\n<p>\u8bf7\u6ce8\u610f\uff0c<code>fetch<\/code>\u89c4\u8303\u4e0e<code>jQuery.ajax()<\/code>\u4e3b\u8981\u6709\u4e24\u79cd\u65b9\u5f0f\u7684\u4e0d\u540c\uff0c\u7262\u8bb0\uff1a<\/p>\n<ul>\n<li>\u5f53\u63a5\u6536\u5230\u4e00\u4e2a\u4ee3\u8868\u9519\u8bef\u7684 HTTP \u72b6\u6001\u7801\u65f6\uff0c\u4ece <code>fetch()<\/code>\u8fd4\u56de\u7684 Promise <strong>\u4e0d\u4f1a\u88ab\u6807\u8bb0\u4e3a reject\uff0c<\/strong> \u5373\u4f7f\u8be5 HTTP \u54cd\u5e94\u7684\u72b6\u6001\u7801\u662f 404 \u6216 500\u3002\u76f8\u53cd\uff0c\u5b83\u4f1a\u5c06 Promise \u72b6\u6001\u6807\u8bb0\u4e3a resolve \uff08\u4f46\u662f\u4f1a\u5c06 resolve \u7684\u8fd4\u56de\u503c\u7684 <code>ok<\/code> \u5c5e\u6027\u8bbe\u7f6e\u4e3a false \uff09\uff0c\u4ec5\u5f53\u7f51\u7edc\u6545\u969c\u65f6\u6216\u8bf7\u6c42\u88ab\u963b\u6b62\u65f6\uff0c\u624d\u4f1a\u6807\u8bb0\u4e3a reject\u3002<\/li>\n<li>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c<code>fetch<\/code> <strong>\u4e0d\u4f1a\u4ece\u670d\u52a1\u7aef\u53d1\u9001\u6216\u63a5\u6536\u4efb\u4f55 cookies<\/strong>, \u5982\u679c\u7ad9\u70b9\u4f9d\u8d56\u4e8e\u7528\u6237 session\uff0c\u5219\u4f1a\u5bfc\u81f4\u672a\u7ecf\u8ba4\u8bc1\u7684\u8bf7\u6c42\uff08\u8981\u53d1\u9001 cookies\uff0c\u5fc5\u987b\u8bbe\u7f6e <a href=\"https:\/\/developer.mozilla.org\/zh-CN\/docs\/web\/api\/fetch#%E5%8F%82%E6%95%B0\">credentials<\/a> \u9009\u9879\uff09\u3002\u81ea\u4ece2017\u5e748\u670825\u65e5\u540e\uff0c\u9ed8\u8ba4\u7684credentials\u653f\u7b56\u53d8\u66f4\u4e3a<code>same-origin<\/code>Firefox\u4e5f\u572861.0b13\u4e2d\u6539\u53d8\u9ed8\u8ba4\u503c<\/li>\n<\/ul>\n<h2>\u8fdb\u884c fetch \u8bf7\u6c42<\/h2>\n<p>\u4e00\u4e2a\u57fa\u672c\u7684 fetch\u8bf7\u6c42\u8bbe\u7f6e\u8d77\u6765\u5f88\u7b80\u5355\u3002\u770b\u770b\u4e0b\u9762\u7684\u4ee3\u7801\uff1a<\/p>\n<pre><code>fetch(&#039;http:\/\/example.com\/movies.json&#039;)\n  .then(function(response) {\n    return response.json();\n  })\n  .then(function(myJson) {\n    console.log(myJson);\n  });\n<\/code><\/pre>\n<p>\u8fd9\u91cc\u6211\u4eec\u901a\u8fc7\u7f51\u7edc\u83b7\u53d6\u4e00\u4e2aJSON\u6587\u4ef6\u5e76\u5c06\u5176\u6253\u5370\u5230\u63a7\u5236\u53f0\u3002\u6700\u7b80\u5355\u7684\u7528\u6cd5\u662f\u53ea\u63d0\u4f9b\u4e00\u4e2a\u53c2\u6570\u7528\u6765\u6307\u660e\u60f3<code>fetch()<\/code>\u5230\u7684\u8d44\u6e90\u8def\u5f84\uff0c\u7136\u540e\u8fd4\u56de\u4e00\u4e2a\u5305\u542b\u54cd\u5e94\u7ed3\u679c\u7684promise(\u4e00\u4e2a <code>Response<\/code> \u5bf9\u8c61)\u3002<\/p>\n<p>\u5f53\u7136\u5b83\u53ea\u662f\u4e00\u4e2a HTTP \u54cd\u5e94\uff0c\u800c\u4e0d\u662f\u771f\u7684JSON\u3002\u4e3a\u4e86\u83b7\u53d6JSON\u7684\u5185\u5bb9\uff0c\u6211\u4eec\u9700\u8981\u4f7f\u7528 <code>json()<\/code>\u65b9\u6cd5\uff08\u5728<code>Body<\/code>mixin \u4e2d\u5b9a\u4e49\uff0c\u88ab <code>Request<\/code> \u548c <code>Response<\/code> \u5bf9\u8c61\u5b9e\u73b0\uff09\u3002<\/p>\n<p><strong>\u6ce8\u610f<\/strong>\uff1aBody mixin \u8fd8\u6709\u5176\u4ed6\u76f8\u4f3c\u7684\u65b9\u6cd5\uff0c\u7528\u4e8e\u83b7\u53d6\u5176\u4ed6\u7c7b\u578b\u7684\u5185\u5bb9\u3002\u53c2\u8003 <a href=\"https:\/\/developer.mozilla.org\/zh-CN\/docs\/Web\/API\/Fetch_API\/Using_Fetch#body\">Body<\/a>\u3002<\/p>\n<p>\u6700\u597d\u4f7f\u7528\u7b26\u5408\u5185\u5bb9\u5b89\u5168\u7b56\u7565 (CSP)\u7684\u94fe\u63a5\u800c\u4e0d\u662f\u4f7f\u7528\u76f4\u63a5\u6307\u5411\u8d44\u6e90\u5730\u5740\u7684\u65b9\u5f0f\u6765\u8fdb\u884cFetch\u7684\u8bf7\u6c42\u3002<\/p>\n<h2>\u652f\u6301\u7684\u8bf7\u6c42\u53c2\u6570<\/h2>\n<p><code>fetch()<\/code> \u63a5\u53d7\u7b2c\u4e8c\u4e2a\u53ef\u9009\u53c2\u6570\uff0c\u4e00\u4e2a\u53ef\u4ee5\u63a7\u5236\u4e0d\u540c\u914d\u7f6e\u7684 <code>init<\/code> \u5bf9\u8c61\uff1a<\/p>\n<p>\u53c2\u8003 <a href=\"https:\/\/developer.mozilla.org\/zh-CN\/docs\/web\/api\/fetch\">fetch()<\/a>\uff0c\u67e5\u770b\u6240\u6709\u53ef\u9009\u7684\u914d\u7f6e\u548c\u66f4\u591a\u63cf\u8ff0\u3002<\/p>\n<pre><code>\/\/ Example POST method implementation:\n\npostData(&#039;http:\/\/example.com\/answer&#039;, {answer: 42})\n  .then(data =&gt; console.log(data)) \/\/ JSON from \\`response.json()\\` call\n  .catch(error =&gt; console.error(error))\n\nfunction postData(url, data) {\n  \/\/ Default options are marked with \\*\n  return fetch(url, {\n    body: JSON.stringify(data), \/\/ must match &#039;Content-Type&#039; header\n    cache: &#039;no-cache&#039;, \/\/ \\*default, no-cache, reload, force-cache, only-if-cached\n    credentials: &#039;same-origin&#039;, \/\/ include, same-origin, \\*omit\n    headers: {\n      &#039;user-agent&#039;: &#039;Mozilla\/4.0 MDN Example&#039;,\n      &#039;content-type&#039;: &#039;application\/json&#039;\n    },\n    method: &#039;POST&#039;, \/\/ \\*GET, POST, PUT, DELETE, etc.\n    mode: &#039;cors&#039;, \/\/ no-cors, cors, \\*same-origin\n    redirect: &#039;follow&#039;, \/\/ manual, \\*follow, error\n    referrer: &#039;no-referrer&#039;, \/\/ \\*client, no-referrer\n  })\n  .then(response =&gt; response.json()) \/\/ parses response to JSON\n}\n<\/code><\/pre>\n<h2>\u53d1\u9001\u5e26\u51ed\u636e\u7684\u8bf7\u6c42<\/h2>\n<p>\u4e3a\u4e86\u8ba9\u6d4f\u89c8\u5668\u53d1\u9001\u5305\u542b\u51ed\u636e\u7684\u8bf7\u6c42\uff08\u5373\u4f7f\u662f\u8de8\u57df\u6e90\uff09\uff0c\u8981\u5c06<code>credentials: &#039;include&#039;<\/code>\u6dfb\u52a0\u5230\u4f20\u9012\u7ed9 <code>fetch()<\/code>\u65b9\u6cd5\u7684<code>init<\/code>\u5bf9\u8c61\u3002<\/p>\n<pre><code>fetch(&#039;https:\/\/example.com&#039;, {\n  credentials: &#039;include&#039;\n})\n<\/code><\/pre>\n<p>\u5982\u679c\u4f60\u53ea\u60f3\u5728\u8bf7\u6c42URL\u4e0e\u8c03\u7528\u811a\u672c\u4f4d\u4e8e\u540c\u4e00\u8d77\u6e90\u5904\u65f6\u53d1\u9001\u51ed\u636e\uff0c\u8bf7\u6dfb\u52a0<code>credentials: &#039;same-origin&#039;<\/code>\u3002<\/p>\n<pre><code>\/\/ The calling script is on the origin &#039;https:\/\/example.com&#039;\n\nfetch(&#039;https:\/\/example.com&#039;, {\n  credentials: &#039;same-origin&#039;\n})\n<\/code><\/pre>\n<p>\u8981\u6539\u4e3a\u786e\u4fdd\u6d4f\u89c8\u5668\u4e0d\u5728\u8bf7\u6c42\u4e2d\u5305\u542b\u51ed\u636e\uff0c\u8bf7\u4f7f\u7528<code>credentials: &#039;omit&#039;<\/code>\u3002<\/p>\n<pre><code>fetch(&#039;https:\/\/example.com&#039;, {\n  credentials: &#039;omit&#039;\n})\n<\/code><\/pre>\n<h2>\u4e0a\u4f20 JSON \u6570\u636e<\/h2>\n<p>\u4f7f\u7528 <code>fetch()<\/code> POST JSON\u6570\u636e<\/p>\n<pre><code>var url = &#039;https:\/\/example.com\/profile&#039;;\nvar data = {username: &#039;example&#039;};\n\nfetch(url, {\n  method: &#039;POST&#039;, \/\/ or &#039;PUT&#039;\n  body: JSON.stringify(data), \/\/ data can be \\`string\\` or {object}!\n  headers: new Headers({\n    &#039;Content-Type&#039;: &#039;application\/json&#039;\n  })\n}).then(res =&gt; res.json())\n.catch(error =&gt; console.error(&#039;Error:&#039;, error))\n.then(response =&gt; console.log(&#039;Success:&#039;, response));\n<\/code><\/pre>\n<h2>\u4e0a\u4f20\u6587\u4ef6<\/h2>\n<p>\u53ef\u4ee5\u901a\u8fc7HTML<code>&lt;input type=&quot;file&quot; \/&gt;<\/code>\u5143\u7d20\uff0c<code>FormData()<\/code> \u548c<code>fetch()<\/code>\u4e0a\u4f20\u6587\u4ef6\u3002<\/p>\n<pre><code>var formData = new FormData();\nvar fileField = document.querySelector(&quot;input\\[type=&#039;file&#039;\\]&quot;);\n\nformData.append(&#039;username&#039;, &#039;abc123&#039;);\nformData.append(&#039;avatar&#039;, fileField.files\\[0\\]);\n\nfetch(&#039;https:\/\/example.com\/profile\/avatar&#039;, {\n  method: &#039;PUT&#039;,\n  body: formData\n})\n.then(response =&gt; response.json())\n.catch(error =&gt; console.error(&#039;Error:&#039;, error))\n.then(response =&gt; console.log(&#039;Success:&#039;, response));\n<\/code><\/pre>\n<h2>\u4e0a\u4f20\u591a\u4e2a\u6587\u4ef6<\/h2>\n<p>\u53ef\u4ee5\u901a\u8fc7HTML<code>&lt;input type=&quot;file&quot; mutiple\/&gt;<\/code>\u5143\u7d20\uff0c<code>FormData()<\/code> \u548c<code>fetch()<\/code>\u4e0a\u4f20\u6587\u4ef6\u3002<\/p>\n<pre><code>var formData = new FormData();\nvar photos = document.querySelector(&quot;input\\[type=&#039;file&#039;\\]\\[multiple\\]&quot;);\n\nformData.append(&#039;title&#039;, &#039;My Vegas Vacation&#039;);\nformData.append(&#039;photos&#039;, photos.files);\n\nfetch(&#039;https:\/\/example.com\/posts&#039;, {\n  method: &#039;POST&#039;,\n  body: formData\n})\n.then(response =&gt; response.json())\n.then(response =&gt; console.log(&#039;Success:&#039;, JSON.stringify(response)))\n.catch(error =&gt; console.error(&#039;Error:&#039;, error));\n<\/code><\/pre>\n<h2>\u68c0\u6d4b\u8bf7\u6c42\u662f\u5426\u6210\u529f<\/h2>\n<p>\u5982\u679c\u9047\u5230\u7f51\u7edc\u6545\u969c\uff0c<code>fetch()<\/code> promise \u5c06\u4f1a reject\uff0c\u5e26\u4e0a\u4e00\u4e2a <code>TypeError<\/code> \u5bf9\u8c61\u3002\u867d\u7136\u8fd9\u4e2a\u60c5\u51b5\u7ecf\u5e38\u662f\u9047\u5230\u4e86\u6743\u9650\u95ee\u9898\u6216\u7c7b\u4f3c\u95ee\u9898\u2014\u2014\u6bd4\u5982 404 \u4e0d\u662f\u4e00\u4e2a\u7f51\u7edc\u6545\u969c\u3002\u60f3\u8981\u7cbe\u786e\u7684\u5224\u65ad <code>fetch()<\/code> \u662f\u5426\u6210\u529f\uff0c\u9700\u8981\u5305\u542b promise resolved \u7684\u60c5\u51b5\uff0c\u6b64\u65f6\u518d\u5224\u65ad <code>Response.ok<\/code> \u662f\u4e0d\u662f\u4e3a true\u3002\u7c7b\u4f3c\u4ee5\u4e0b\u4ee3\u7801\uff1a<\/p>\n<pre><code>fetch(&#039;flowers.jpg&#039;).then(function(response) {\n  if(response.ok) {\n    return response.blob();\n  }\n  throw new Error(&#039;Network response was not ok.&#039;);\n}).then(function(myBlob) {\n  var objectURL = URL.createObjectURL(myBlob);\n  myImage.src = objectURL;\n}).catch(function(error) {\n  console.log(&#039;There has been a problem with your fetch operation: &#039;, error.message);\n});\n<\/code><\/pre>\n<h2>\u81ea\u5b9a\u4e49\u8bf7\u6c42\u5bf9\u8c61<\/h2>\n<p>\u9664\u4e86\u4f20\u7ed9 <code>fetch()<\/code> \u4e00\u4e2a\u8d44\u6e90\u7684\u5730\u5740\uff0c\u4f60\u8fd8\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528 <code>Request()<\/code> \u6784\u9020\u51fd\u6570\u6765\u521b\u5efa\u4e00\u4e2a request \u5bf9\u8c61\uff0c\u7136\u540e\u518d\u4f5c\u4e3a\u53c2\u6570\u4f20\u7ed9 <code>fetch()<\/code>\uff1a<\/p>\n<pre><code>var myHeaders = new Headers();\n\nvar myInit = { method: &#039;GET&#039;,\n               headers: myHeaders,\n               mode: &#039;cors&#039;,\n               cache: &#039;default&#039; };\n\nvar myRequest = new Request(&#039;flowers.jpg&#039;, myInit);\n\nfetch(myRequest).then(function(response) {\n  return response.blob();\n}).then(function(myBlob) {\n  var objectURL = URL.createObjectURL(myBlob);\n  myImage.src = objectURL;\n});\n<\/code><\/pre>\n<p><code>Request()<\/code> \u548c <code>fetch()<\/code> \u63a5\u53d7\u540c\u6837\u7684\u53c2\u6570\u3002\u4f60\u751a\u81f3\u53ef\u4ee5\u4f20\u5165\u4e00\u4e2a\u5df2\u5b58\u5728\u7684 request \u5bf9\u8c61\u6765\u521b\u9020\u4e00\u4e2a\u62f7\u8d1d\uff1a<\/p>\n<pre><code>var anotherRequest = new Request(myRequest,myInit);\n<\/code><\/pre>\n<p>\u8fd9\u4e2a\u5f88\u6709\u7528\uff0c\u56e0\u4e3a request \u548c response bodies \u53ea\u80fd\u88ab\u4f7f\u7528\u4e00\u6b21\uff08\u8bd1\u8005\u6ce8\uff1a\u8fd9\u91cc\u7684\u610f\u601d\u662f\u56e0\u4e3a\u8bbe\u8ba1\u6210\u4e86 stream \u7684\u65b9\u5f0f\uff0c\u6240\u4ee5\u5b83\u4eec\u53ea\u80fd\u88ab\u8bfb\u53d6\u4e00\u6b21\uff09\u3002\u521b\u5efa\u4e00\u4e2a\u62f7\u8d1d\u5c31\u53ef\u4ee5\u518d\u6b21\u4f7f\u7528 request\/response \u4e86\uff0c\u5f53\u7136\u4e5f\u53ef\u4ee5\u4f7f\u7528\u4e0d\u540c\u7684 <code>init<\/code> \u53c2\u6570\u3002<\/p>\n<p><strong>\u6ce8\u610f<\/strong>\uff1a<code>clone()<\/code> \u65b9\u6cd5\u4e5f\u53ef\u4ee5\u7528\u4e8e\u521b\u5efa\u4e00\u4e2a\u62f7\u8d1d\u3002\u5b83\u5728\u8bed\u4e49\u4e0a\u6709\u4e00\u70b9\u4e0d\u540c\u4e8e\u5176\u4ed6\u62f7\u8d1d\u7684\u65b9\u6cd5\u3002\u5176\u4ed6\u65b9\u6cd5\uff08\u6bd4\u5982\u62f7\u8d1d\u4e00\u4e2a response\uff09\u4e2d\uff0c\u5982\u679c request \u7684 body \u5df2\u7ecf\u88ab\u8bfb\u53d6\u8fc7\uff0c\u90a3\u4e48\u5c06\u6267\u884c\u5931\u8d25\uff0c\u7136\u800c <code>clone()<\/code> \u5219\u4e0d\u4f1a\u5931\u8d25\u3002<\/p>\n<h2>Headers<\/h2>\n<p>\u4f7f\u7528 <code>Headers<\/code> \u7684\u63a5\u53e3\uff0c\u4f60\u53ef\u4ee5\u901a\u8fc7 <code>Headers()<\/code> \u6784\u9020\u51fd\u6570\u6765\u521b\u5efa\u4e00\u4e2a\u4f60\u81ea\u5df1\u7684 headers \u5bf9\u8c61\u3002\u4e00\u4e2a headers \u5bf9\u8c61\u662f\u4e00\u4e2a\u7b80\u5355\u7684\u591a\u540d\u503c\u5bf9\uff1a<\/p>\n<pre><code>var content = &quot;Hello World&quot;;\nvar myHeaders = new Headers();\nmyHeaders.append(&quot;Content-Type&quot;, &quot;text\/plain&quot;);\nmyHeaders.append(&quot;Content-Length&quot;, content.length.toString());\nmyHeaders.append(&quot;X-Custom-Header&quot;, &quot;ProcessThisImmediately&quot;);\n<\/code><\/pre>\n<p>\u4e5f\u53ef\u4ee5\u4f20\u4e00\u4e2a\u591a\u7ef4\u6570\u7ec4\u6216\u8005\u5bf9\u8c61\u5b57\u9762\u91cf\uff1a<\/p>\n<pre><code>myHeaders = new Headers({\n  &quot;Content-Type&quot;: &quot;text\/plain&quot;,\n  &quot;Content-Length&quot;: content.length.toString(),\n  &quot;X-Custom-Header&quot;: &quot;ProcessThisImmediately&quot;,\n});\n<\/code><\/pre>\n<p>\u5b83\u7684\u5185\u5bb9\u53ef\u4ee5\u88ab\u83b7\u53d6\uff1a<\/p>\n<pre><code>console.log(myHeaders.has(&quot;Content-Type&quot;)); \/\/ true\nconsole.log(myHeaders.has(&quot;Set-Cookie&quot;)); \/\/ false\nmyHeaders.set(&quot;Content-Type&quot;, &quot;text\/html&quot;);\nmyHeaders.append(&quot;X-Custom-Header&quot;, &quot;AnotherValue&quot;);\n\nconsole.log(myHeaders.get(&quot;Content-Length&quot;)); \/\/ 11\nconsole.log(myHeaders.getAll(&quot;X-Custom-Header&quot;)); \/\/ \\[&quot;ProcessThisImmediately&quot;, &quot;AnotherValue&quot;\\]\n\nmyHeaders.delete(&quot;X-Custom-Header&quot;);\nconsole.log(myHeaders.getAll(&quot;X-Custom-Header&quot;)); \/\/ \\[ \\]\n<\/code><\/pre>\n<p>\u867d\u7136\u4e00\u4e9b\u64cd\u4f5c\u53ea\u80fd\u5728 <code>ServiceWorkers<\/code> \u4e2d\u4f7f\u7528\uff0c\u4f46\u662f\u5b83\u63d0\u4f9b\u4e86\u66f4\u65b9\u4fbf\u7684\u64cd\u4f5c Headers \u7684 API\u3002<\/p>\n<p>\u5982\u679c\u4f7f\u7528\u4e86\u4e00\u4e2a\u4e0d\u5408\u6cd5\u7684HTTP Header\u5c5e\u6027\u540d\uff0c\u90a3\u4e48Headers\u7684\u65b9\u6cd5\u901a\u5e38\u90fd\u629b\u51fa TypeError \u5f02\u5e38\u3002\u5982\u679c\u4e0d\u5c0f\u5fc3\u5199\u5165\u4e86\u4e00\u4e2a\u4e0d\u53ef\u5199\u7684\u5c5e\u6027\uff0c\u4e5f\u4f1a\u629b\u51fa\u4e00\u4e2a TypeError \u5f02\u5e38\u3002\u9664\u6b64\u4ee5\u5916\u7684\u60c5\u51b5\uff0c\u5931\u8d25\u4e86\u5e76\u4e0d\u629b\u51fa\u5f02\u5e38\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>var myResponse = Response.error();\ntry {\n  myResponse.headers.set(&quot;Origin&quot;, &quot;http:\/\/mybank.com&quot;);\n} catch(e) {\n  console.log(&quot;Cannot pretend to be a bank!&quot;);\n}\n<\/code><\/pre>\n<p>\u6700\u4f73\u5b9e\u8df5\u662f\u5728\u4f7f\u7528\u4e4b\u524d\u68c0\u67e5 content type \u662f\u5426\u6b63\u786e\uff0c\u6bd4\u5982\uff1a<\/p>\n<pre><code>fetch(myRequest).then(function(response) {\n  if(response.headers.get(&quot;content-type&quot;) === &quot;application\/json&quot;) {\n    return response.json().then(function(json) {\n      \/\/ process your JSON further\n    });\n  } else {\n    console.log(&quot;Oops, we haven&#039;t got JSON!&quot;);\n  }\n});\n<\/code><\/pre>\n<h2>Guard<\/h2>\n<p>\u7531\u4e8e Headers \u53ef\u4ee5\u5728 request \u8bf7\u6c42\u4e2d\u88ab\u53d1\u9001\u6216\u8005\u5728 response \u8bf7\u6c42\u4e2d\u88ab\u63a5\u6536\uff0c\u5e76\u4e14\u89c4\u5b9a\u4e86\u54ea\u4e9b\u53c2\u6570\u662f\u53ef\u5199\u7684\uff0cHeaders \u5bf9\u8c61\u6709\u4e00\u4e2a\u7279\u6b8a\u7684 guard \u5c5e\u6027\u3002\u8fd9\u4e2a\u5c5e\u6027\u6ca1\u6709\u66b4\u9732\u7ed9 Web\uff0c\u4f46\u662f\u5b83\u5f71\u54cd\u5230\u54ea\u4e9b\u5185\u5bb9\u53ef\u4ee5\u5728 Headers \u5bf9\u8c61\u4e2d\u88ab\u64cd\u4f5c\u3002<\/p>\n<p>\u53ef\u80fd\u7684\u503c\u5982\u4e0b\uff1a<\/p>\n<ul>\n<li><code>none<\/code>\uff1a\u9ed8\u8ba4\u7684<\/li>\n<li><code>request<\/code>\uff1a\u4ece request \u4e2d\u83b7\u5f97\u7684 headers\uff08<code>Request.headers<\/code>\uff09\u53ea\u8bfb<\/li>\n<li><code>request-no-cors<\/code>\uff1a\u4ece\u4e0d\u540c\u57df\uff08<code>Request.mode<\/code> <code>no-cors<\/code>\uff09\u7684 request \u4e2d\u83b7\u5f97\u7684 headers \u53ea\u8bfb<\/li>\n<li><code>response<\/code>\uff1a\u4ece response \u4e2d\u83b7\u5f97\u7684 headers\uff08<code>Response.headers<\/code>\uff09\u53ea\u8bfb<\/li>\n<li><code>immutable<\/code>\uff1a\u5728 ServiceWorkers \u4e2d\u6700\u5e38\u7528\u7684\uff0c\u6240\u6709\u7684 headers \u90fd\u53ea\u8bfb\u3002<\/li>\n<\/ul>\n<p><strong>\u6ce8\u610f<\/strong>\uff1a\u4f60\u4e0d\u53ef\u4ee5\u6dfb\u52a0\u6216\u8005\u4fee\u6539\u4e00\u4e2a guard \u5c5e\u6027\u662f <code>request<\/code> \u7684 Request Headers \u7684 <code>Content-Length<\/code> \u5c5e\u6027\u3002\u540c\u6837\u5730\uff0c\u63d2\u5165 <code>Set-Cookie<\/code> \u5c5e\u6027\u5230\u4e00\u4e2a response headers \u662f\u4e0d\u5141\u8bb8\u7684\uff0c\u56e0\u6b64 ServiceWorkers \u662f\u4e0d\u80fd\u7ed9\u5408\u6210\u7684 Response \u7684 headers \u6dfb\u52a0\u4e00\u4e9b cookies\u3002<\/p>\n<h2>Response \u5bf9\u8c61<\/h2>\n<p>\u5982\u4e0a\u8ff0, <code>Response<\/code> \u5b9e\u4f8b\u662f\u5728 <code>fetch()<\/code> \u5904\u7406\u5b8cpromises\u4e4b\u540e\u8fd4\u56de\u7684\u3002<\/p>\n<p>\u4f60\u4f1a\u7528\u5230\u7684\u6700\u5e38\u89c1\u7684response\u5c5e\u6027\u6709:<\/p>\n<ul>\n<li><code>Response.status<\/code> \u2014 \u6574\u6570(\u9ed8\u8ba4\u503c\u4e3a200) \u4e3aresponse\u7684\u72b6\u6001\u7801.<\/li>\n<li><code>Response.statusText<\/code> \u2014 \u5b57\u7b26\u4e32(\u9ed8\u8ba4\u503c\u4e3a&quot;OK&quot;),\u8be5\u503c\u4e0eHTTP\u72b6\u6001\u7801\u6d88\u606f\u5bf9\u5e94.<\/li>\n<li><code>Response.ok<\/code> \u2014 \u5982\u4e0a\u6240\u793a, \u8be5\u5c5e\u6027\u662f\u6765\u68c0\u67e5response\u7684\u72b6\u6001\u662f\u5426\u5728200-299(\u5305\u62ec200,299)\u8fd9\u4e2a\u8303\u56f4\u5185.\u8be5\u5c5e\u6027\u8fd4\u56de\u4e00\u4e2a<code>Boolean<\/code>\u503c.<\/li>\n<\/ul>\n<p>\u5b83\u7684\u5b9e\u4f8b\u4e5f\u53ef\u7528\u901a\u8fc7 JavaScript \u6765\u521b\u5efa, \u4f46\u53ea\u6709\u5728<code>ServiceWorkers<\/code>\u4e2d\u624d\u771f\u6b63\u6709\u7528,\u5f53\u4f7f\u7528<code>respondWith()<\/code>\u65b9\u6cd5\u5e76\u63d0\u4f9b\u4e86\u4e00\u4e2a\u81ea\u5b9a\u4e49\u7684response\u6765\u63a5\u53d7request\u65f6:<\/p>\n<pre><code>var myBody = new Blob();\n\naddEventListener(&#039;fetch&#039;, function(event) {\n  event.respondWith(new Response(myBody, {\n    headers: { &quot;Content-Type&quot; : &quot;text\/plain&quot; }\n  });\n});\n<\/code><\/pre>\n<p><code>Response()<\/code> \u6784\u9020\u65b9\u6cd5\u63a5\u53d7\u4e24\u4e2a\u53ef\u9009\u53c2\u6570\u2014response\u7684\u6570\u636e\u4f53\u548c\u4e00\u4e2a\u521d\u59cb\u5316\u5bf9\u8c61(\u4e0e<code>Request()<\/code>\u6240\u63a5\u53d7\u7684init\u53c2\u6570\u7c7b\u4f3c.)<\/p>\n<p><strong>\u6ce8\u610f<\/strong>: \u9759\u6001\u65b9\u6cd5<code>error()<\/code>\u53ea\u662f\u8fd4\u56de\u4e86\u4e00\u4e2a\u9519\u8bef\u7684response. \u4e0e\u6b64\u7c7b\u4f3c\u5730, <code>redirect()<\/code> \u53ea\u662f\u8fd4\u56de\u4e86\u4e00\u4e2a\u53ef\u4ee5\u91cd\u5b9a\u5411\u81f3\u67d0URL\u7684response. \u8fd9\u4e9b\u4e5f\u53ea\u4e0eService Workers\u624d\u6709\u5173\u3002<\/p>\n<h2>Body<\/h2>\n<p>\u4e0d\u7ba1\u662f\u8bf7\u6c42\u8fd8\u662f\u54cd\u5e94\u90fd\u80fd\u591f\u5305\u542bbody\u5bf9\u8c61. body\u4e5f\u53ef\u4ee5\u662f\u4ee5\u4e0b\u4efb\u610f\u7c7b\u578b\u7684\u5b9e\u4f8b.<\/p>\n<ul>\n<li><code>ArrayBuffer<\/code><\/li>\n<li><code>ArrayBufferView<\/code> (Uint8Array\u7b49)<\/li>\n<li><code>Blob<\/code>\/File<\/li>\n<li>string<\/li>\n<li><code>URLSearchParams<\/code><\/li>\n<li>[<code>FormData<\/code>](&quot;FormData \u63a5\u53e3\u63d0\u4f9b\u4e86\u4e00\u79cd\u8868\u793a\u8868\u5355\u6570\u636e\u7684\u952e\u503c\u5bf9\u7684\u6784\u9020\u65b9\u5f0f\uff0c\u7ecf\u8fc7\u5b83\u7684\u6570\u636e\u53ef\u4ee5\u4f7f\u7528 XMLHttpRequest.send() \u65b9\u6cd5\u9001\u51fa\uff0c\u672c\u63a5\u53e3\u548c\u6b64\u65b9\u6cd5\u90fd\u76f8\u5f53\u7b80\u5355\u76f4\u63a5\u3002\u5982\u679c\u9001\u51fa\u65f6\u7684\u7f16\u7801\u7c7b\u578b\u88ab\u8bbe\u4e3a &quot;multipart\/form-data&quot;\uff0c\u5b83\u4f1a\u4f7f\u7528\u548c\u8868\u5355\u4e00\u6837\u7684\u683c\u5f0f\u3002&quot;)<\/li>\n<\/ul>\n<p><code>Body<\/code> \u7c7b\u5b9a\u4e49\u4e86\u4ee5\u4e0b\u65b9\u6cd5 (\u8fd9\u4e9b\u65b9\u6cd5\u90fd\u88ab <code>Request<\/code> \u548c<code>Response<\/code>\u6240\u5b9e\u73b0)\u4ee5\u83b7\u53d6body\u5185\u5bb9. \u8fd9\u4e9b\u65b9\u6cd5\u90fd\u4f1a\u8fd4\u56de\u4e00\u4e2a\u88ab\u89e3\u6790\u540e\u7684<code>Promise<\/code>\u5bf9\u8c61\u548c\u6570\u636e.<\/p>\n<ul>\n<li><code>arrayBuffer()<\/code><\/li>\n<li><code>blob()<\/code><\/li>\n<li><code>json()<\/code><\/li>\n<li>[<code>text()<\/code>](&quot;Body\u6df7\u5165\u7684 text() \u65b9\u6cd5\u63d0\u4f9b\u4e86\u4e00\u4e2a\u53ef\u4f9b\u8bfb\u53d6\u7684&quot;\u8fd4\u56de\u6d41&quot;, \u2014\u2014\u5b83\u8fd4\u56de\u4e00\u4e2a\u5305\u542bUSVString\u5bf9\u8c61 (text)\u7684Promise\u5bf9\u8c61\uff0c\u8fd4\u56de\u7ed3\u679c\u7684\u7f16\u7801\u4e3aUTF-8\u3002&quot;)<\/li>\n<li><code>formData()<\/code><\/li>\n<\/ul>\n<p>\u6bd4\u8d77XHR\u6765\uff0c\u8fd9\u4e9b\u65b9\u6cd5\u8ba9\u975e\u6587\u672c\u5316\u7684\u6570\u636e\u4f7f\u7528\u8d77\u6765\u66f4\u52a0\u7b80\u5355\u3002<\/p>\n<p>\u8bf7\u6c42\u4f53\u53ef\u4ee5\u7531\u4f20\u5165body\u53c2\u6570\u6765\u8fdb\u884c\u8bbe\u7f6e:<\/p>\n<pre><code>var form = new FormData(document.getElementById(&#039;login-form&#039;));\nfetch(&quot;\/login&quot;, {\n  method: &quot;POST&quot;,\n  body: form\n})\n<\/code><\/pre>\n<p>request\u548cresponse\uff08\u5305\u62ec<code>fetch()<\/code> \u65b9\u6cd5\uff09\u90fd\u4f1a\u8bd5\u7740\u81ea\u52a8\u8bbe\u7f6e<code>Content-Type<\/code>\u3002\u5982\u679c\u6ca1\u6709\u8bbe\u7f6e<code>Content-Type<\/code>\u503c\uff0c\u53d1\u9001\u7684\u8bf7\u6c42\u4e5f\u4f1a\u81ea\u52a8\u8bbe\u503c\u3002<\/p>\n<h2>\u7279\u6027\u68c0\u6d4b<\/h2>\n<p>Fetch API \u7684\u652f\u6301\u60c5\u51b5\uff0c\u53ef\u4ee5\u901a\u8fc7\u68c0\u6d4b<code>Headers<\/code>, <code>Request<\/code>, <code>Response<\/code> \u6216 <code>fetch()<\/code>\u662f\u5426\u5728<code>Window<\/code> \u6216 <code>Worker<\/code> \u57df\u4e2d\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>if(self.fetch) {\n    \/\/ run my fetch request here\n} else {\n    \/\/ do something with XMLHttpRequest?\n}\n<\/code><\/pre>\n<p>\u672c\u6587\u8f6c\u81ea <a 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