fetch-api

问题 Opaque responses are defined as part of the Fetch API, and represent the result of a request made to a remote origin when CORS is not enabled. What practical limitations and \"gotchas\" exist around how opaque responses can be used, both from JavaScript and as resources on a page? 回答1: Access to Opaque Responses' Headers / Body The most straightforward limitation around opaque responses is that you cannot get meaningful information back from most of the properties of the Response class, like

问题 What does it mean when JavaScript network calls such as fetch or XMLHttpRequest, or any other type of HTTP network request, fail with an HTTP status code of 0? This doesn\'t seem to be a valid HTTP status code as other codes are three digits in HTTP specification. I tried unplugging the network completely as a test. It may be unrelated, but that resulted in status code 17003 (IIRC), which cursory searching suggests means \"DNS server lookup failed\". The same code works fine from some

问题 There is a new API for making requests from JavaScript: fetch(). Is there any built in mechanism for canceling these requests in-flight? 回答1: TL/DR: fetch now supports a signal parameter as of 20 September 2017, but not all browsers seem support this atm . This is a change we will be seeing very soon though, and so you should be able to cancel a request by using an AbortController s AbortSignal . Long Version How to: The way it works is this: Step 1 : You create an AbortController (For now I

问题 I can hit this endpoint, http://catfacts-api.appspot.com/api/facts?number=99 via Postman and it returns JSON Additionally I am using create-react-app and would like to avoid setting up any server config. In my client code I am trying to use fetch to do the same thing, but I get the error: No \'Access-Control-Allow-Origin\' header is present on the requested resource. Origin \'http://localhost:3000\' is therefore not allowed access. If an opaque response serves your needs, set the request\'s

问题 I\'ve been messing around with the fetch() api recently, and noticed something which was a bit quirky. let url = \"http://jsonplaceholder.typicode.com/posts/6\"; let iterator = fetch(url); iterator .then(response => { return { data: response.json(), status: response.status } }) .then(post => document.write(post.data)); ; post.data returns a Promise object. http://jsbin.com/wofulo/2/edit?js,output However if it is written as: let url = \"http://jsonplaceholder.typicode.com/posts/6\"; let

问题 I tried a ReactJS fetch call to a REST-API and want to handle the response. The call works, i get a response, which i can see in Chrome Dev Tools: function getAllCourses() { fetch(\'http://localhost:8080/course\', { method: \'POST\', mode: \'no-cors\', credentials: \'same-origin\', headers: { \'Accept\': \'application/json\', \'Content-Type\': \'application/json\', }, body: JSON.stringify({ objectClass: \'course\', crud: \'2\' }) }).then(function (response) { console.log(response); return

问题 I\'m trying to POST a JSON object using fetch. From what I can understand, I need to attach a stringified object to the body of the request, e.g.: fetch(\"/echo/json/\", { headers: { \'Accept\': \'application/json\', \'Content-Type\': \'application/json\' }, method: \"POST\", body: JSON.stringify({a: 1, b: 2}) }) .then(function(res){ console.log(res) }) .catch(function(res){ console.log(res) }) When using jsfiddle\'s json echo I\'d expect to see the object I\'ve sent ( {a: 1, b: 2} ) back,

问题 I\'m trying to fetch some data from the REST API of HP Alm. It works pretty well with a small curl script - I get my data. Now doing that with JavaScript, fetch and ES6 (more or less) seems to be a bigger issue. I keep getting this error message: Fetch API cannot load . Response to preflight request doesn\'t pass access control check: No \'Access-Control-Allow-Origin\' header is present on the requested resource. Origin \'http://127.0.0.1:3000\' is therefore not allowed access. The response