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request请求
请求不同类型封装
text.js
type.js
d3-request
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import {map} from "d3-collection";
import {dispatch} from "d3-dispatch";
export default function(url, callback) {
var request,
event = dispatch("beforesend", "progress", "load", "error"),
mimeType,
headers = map(),
xhr = new XMLHttpRequest,
user = null,
password = null,
response,
responseType,
timeout = 0;
// If IE does not support CORS, use XDomainRequest.
if (typeof XDomainRequest !== "undefined"
&& !("withCredentials" in xhr)
&& /^(http(s)?:)?\/\//.test(url)) xhr = new XDomainRequest;
// 根据onreadystatechange，readyState 触发respond
"onload" in xhr
? xhr.onload = xhr.onerror = xhr.ontimeout = respond
: xhr.onreadystatechange = function(o) { xhr.readyState > 3 && respond(o); };
function respond(o) {
var status = xhr.status, result;
if (!status && hasResponse(xhr)
|| status >= 200 && status < 300
|| status === 304) {
if (response) {
try {
result = response.call(request, xhr);
} catch (e) {
event.call("error", request, e);
return;
}
} else {
result = xhr;
}
event.call("load", request, result);
} else {
event.call("error", request, o);
}
}
xhr.onprogress = function(e) {
event.call("progress", request, e);
};
request = {
// 设置header
header: function(name, value) {
name = (name + "").toLowerCase();
if (arguments.length < 2) return headers.get(name);
if (value == null) headers.remove(name);
else headers.set(name, value + "");
return request;
},
// 设置mimeType
// If mimeType is non-null and no Accept header is set, a default is used.
mimeType: function(value) {
if (!arguments.length) return mimeType;
mimeType = value == null ? null : value + "";
return request;
},
// Specifies what type the response value should take;
// for instance, arraybuffer, blob, document, or text.
responseType: function(value) {
if (!arguments.length) return responseType;
responseType = value;
return request;
},
timeout: function(value) {
if (!arguments.length) return timeout;
timeout = +value;
return request;
},
user: function(value) {
return arguments.length < 1 ? user : (user = value == null ? null : value + "", request);
},
password: function(value) {
return arguments.length < 1 ? password : (password = value == null ? null : value + "", request);
},
// Specify how to convert the response content to a specific type;
// changes the callback value on "load" events.
response: function(value) {
response = value;
return request;
},
// Alias for send("GET", …).
get: function(data, callback) {
return request.send("GET", data, callback);
},
// Alias for send("POST", …).
post: function(data, callback) {
return request.send("POST", data, callback);
},
// If callback is non-null, it will be used for error and load events.
send: function(method, data, callback) {
xhr.open(method, url, true, user, password);
if (mimeType != null && !headers.has("accept")) headers.set("accept", mimeType + ",*/*");
if (xhr.setRequestHeader) headers.each(function(value, name) { xhr.setRequestHeader(name, value); });
if (mimeType != null && xhr.overrideMimeType) xhr.overrideMimeType(mimeType);
if (responseType != null) xhr.responseType = responseType;
if (timeout > 0) xhr.timeout = timeout;
if (callback == null && typeof data === "function") callback = data, data = null;
if (callback != null && callback.length === 1) callback = fixCallback(callback);
if (callback != null) request.on("error", callback).on("load", function(xhr) { callback(null, xhr); });
event.call("beforesend", request, xhr);
xhr.send(data == null ? null : data);
return request;
},
abort: function() {
xhr.abort();
return request;
},
on: function() {
var value = event.on.apply(event, arguments);
return value === event ? request : value;
}
};
if (callback != null) {
if (typeof callback !== "function") throw new Error("invalid callback: " + callback);
return request.get(callback);
}
return request;
}
function fixCallback(callback) {
return function(error, xhr) {
callback(error == null ? xhr : null);
};
}
function hasResponse(xhr) {
var type = xhr.responseType;
return type && type !== "text"
? xhr.response // null on error
: xhr.responseText; // "" on error
}
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d3.text("/path/to/file.txt", function(error, text) {
if (error) throw error;
console.log(text); // Hello, world!
});
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import type from "./type";
export default type("text/plain", function(xhr) {
return xhr.responseText;
});
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import request from "./request";
export default function(defaultMimeType, response) {
return function(url, callback) {
var r = request(url).mimeType(defaultMimeType).response(response);
if (callback != null) {
if (typeof callback !== "function") throw new Error("invalid callback: " + callback);
return r.get(callback);
}
return r;
};
}