dojo ajax 传参

dojo ajax 传参

If you were to ask me for the top five words that should describe any JavaScript framework, one of them would be flexible.  The Dojo Toolkit is ultra-flexible in just about every way, using customizable classes and dojo-namespaced objects to to allow for maximal flexibility.  One of those dojo-namespaced objects, dojo.contentHandlers, is an object containing key->value pairs for handling the result of AJAX requests.  Let me show you how to use these content handlers and how you can create your own!

如果您要问我描述任何JavaScript框架的前五个词，那么其中一个会很灵活。 Dojo Toolkit在几乎所有方面都非常灵活，它使用可定制的类和dojo命名空间对象来实现最大的灵活性。 那些dojo -namespaced对象之一dojo.contentHandlers是一个包含键->值对的对象，用于处理AJAX请求的结果。 让我向您展示如何使用这些内容处理程序以及如何创建自己的内容处理程序！

dojo.xhr和handleAs (dojo.xhr and handleAs)

Making AJAX requests is done with Dojo's dojo.xhr methods.  Sending a basic GET request would look like:

发出AJAX请求是通过Dojo的dojo.xhr方法完成的。 发送基本的GET请求如下所示：

dojo.xhrGet({ url: "/ajax.php", load: function(result) { // Do something with the result here } });

The request above assumes that the response should be handled as plain text, as you would expect.  Dojo's dojo.xhr methods all accept an object with properties for handling the request, and one property you can add is handleAs.  The handleAs property should be a string representing the type of parsing that should be done to the result before its passed to the load method or deferred callback.  Values for the handleAs property could be json, javascript, xml, or other variants of json.  If I want my request to be handled as JSON, I'd code:

上面的请求假定响应应该像您期望的那样以纯文本形式进行处理。 Dojo的dojo.xhr方法都接受一个具有用于处理请求的属性的对象，可以添加的一个属性是handleAs 。 handleAs属性应该是一个字符串，表示在将结果传递给load方法或递延回调之前应对结果进行的解析类型。 handleAs属性的值可以是json，javascript，xml或json的其他变体。 如果我希望将请求处理为JSON，请编写以下代码：

dojo.xhrGet({ url: "/ajax.php", handleAs: "json", load: function(result) { // result is a JS object // Do something with the result here } });

The resulting object provided to the load handler is text parsed into JavaScript object.  Likewise, if I want the result to be handled as XML, I'd code:

提供给加载处理程序的结果对象将文本解析为JavaScript对象。 同样，如果我希望将结果作为XML处理，我将编写代码：

dojo.xhrGet({ url: "/ajax.php", handleAs: "xml", load: function(result) { // result is a XMLDocument object // Do something with the result here } });

The load callback is provided a XMLDocument object.  One simple parameter changes the way the request response is parsed.  So how is this possible, and how can you create custom handleAs methods?  Simple!

加载回调提供了XMLDocument对象。 一个简单的参数更改了请求响应的解析方式。 那么，这怎么可能？如何创建自定义的handleAs方法？ 简单！

dojo.contentHandlers (dojo.contentHandlers)

The dojo.contentHandlers object acts as dictionary for ajax request parsing.  The handleAs parameter you  supply maps to the key within dojo.contentHandlers.  The dojo.contentHandlers object comes with the following content handlers:  javascript, json, json-comment-filtered, json-comment-optional, text, and xml.  Here's a snippet containing those "parsers":

dojo.contentHandlers对象充当ajax请求解析的字典。 您提供的handleAs参数映射到dojo.contentHandlers的键。 dojo.contentHandlers对象带有以下内容处理程序：javascript，json，json-comment-filtered，json-comment-optional，text和xml。 这是包含这些“解析器”的代码段：

var handlers = dojo._contentHandlers = dojo.contentHandlers = { text: function(xhr){ // summary: A contentHandler which simply returns the plaintext response data return xhr.responseText; }, json: function(xhr){ // summary: A contentHandler which returns a JavaScript object created from the response data return _d.fromJson(xhr.responseText || null); }, "json-comment-filtered": function(xhr){ if(!dojo.config.useCommentedJson){ console.warn("Consider using the standard mimetype:application/json." + " json-commenting can introduce security issues. To" + " decrease the chances of hijacking, use the standard the 'json' handler and" + " prefix your json with: {}&&\n" + "Use djConfig.useCommentedJson=true to turn off this message."); } var value = xhr.responseText; var cStartIdx = value.indexOf("\/*"); var cEndIdx = value.lastIndexOf("*\/"); if(cStartIdx == -1 || cEndIdx == -1){ throw new Error("JSON was not comment filtered"); } return _d.fromJson(value.substring(cStartIdx+2, cEndIdx)); }, javascript: function(xhr){ // summary: A contentHandler which evaluates the response data, expecting it to be valid JavaScript // FIXME: try Moz and IE specific eval variants? return _d.eval(xhr.responseText); }, xml: function(xhr){ // summary: A contentHandler returning an XML Document parsed from the response data var result = xhr.responseXML; //>>excludeStart("webkitMobile", kwArgs.webkitMobile); if(_d.isIE && (!result || !result.documentElement)){ //WARNING: this branch used by the xml handling in dojo.io.iframe, //so be sure to test dojo.io.iframe if making changes below. var ms = function(n){ return "MSXML" + n + ".DOMDocument"; } var dp = ["Microsoft.XMLDOM", ms(6), ms(4), ms(3), ms(2)]; _d.some(dp, function(p){ try{ var dom = new ActiveXObject(p); dom.async = false; dom.loadXML(xhr.responseText); result = dom; }catch(e){ return false; } return true; }); } //>>excludeEnd("webkitMobile"); return result; // DOMDocument }, "json-comment-optional": function(xhr){ // summary: A contentHandler which checks the presence of comment-filtered JSON and // alternates between the `json` and `json-comment-filtered` contentHandlers. if(xhr.responseText && /^[^{\[]*\/\*/.test(xhr.responseText)){ return handlers["json-comment-filtered"](xhr); }else{ return handlers["json"](xhr); } } };

What if we want to add our own content handler though?  All you need to do is add the key=>parser to the dojo.contentHandlers object!

如果我们想添加自己的内容处理程序怎么办？ 您需要做的就是将key => parser添加到dojo.contentHandlers对象！

// CSV parsing found at: http://stackoverflow.com/questions/1293147/javascript-code-to-parse-csv-data dojo.contentHandlers.csv = function(xhr) { // Set the data var responseText = xhr.responseText; var delimiter = ","; // Create a regular expression to parse the CSV values. var objPattern = new RegExp( ( // Delimiters. "(\\" + delimiter + "|\\r?\\n|\\r|^)" + // Quoted fields. "(?:\"([^\"]*(?:\"\"[^\"]*)*)\"|" + // Standard fields. "([^\"\\" + delimiter + "\\r\\n]*))" ), "gi"); // Create an array to hold our data. Give the array // a default empty first row. var arrData = [[]]; // Create an array to hold our individual pattern // matching groups. var arrMatches = null; // Keep looping over the regular expression matches // until we can no longer find a match. while (arrMatches = objPattern.exec(responseText)){ // Get the delimiter that was found. var strMatchedDelimiter = arrMatches[1]; // Check to see if the given delimiter has a length // (is not the start of string) and if it matches // field delimiter. If id does not, then we know // that this delimiter is a row delimiter. if (strMatchedDelimiter.length && (strMatchedDelimiter != delimiter)){ // Since we have reached a new row of data, // add an empty row to our data array. arrData.push([]); } // Now that we have our delimiter out of the way, // let's check to see which kind of value we // captured (quoted or unquoted). if (arrMatches[2]){ // We found a quoted value. When we capture // this value, unescape any double quotes. var strMatchedValue = arrMatches[2].replace( new RegExp("\"\"", "g"), "\"" ); } else { // We found a non-quoted value. var strMatchedValue = arrMatches[3]; } // Now that we have our value string, let's add // it to the data array. arrData[arrData.length - 1].push(strMatchedValue); } // Return the parsed data. return(arrData); }

The code snippet above allows you to have your XHR request's result be parsed as CSV content;  the result becomes a JavaScript object representing the CSV data.  Here's how you'd use it:

上面的代码段使您可以将XHR请求的结果解析为CSV内容； 结果将成为表示CSV数据JavaScript对象。 使用方法如下：

dojo.xhrGet({ url: "/ajax.php", handleAs: "csv", load: function(result) { // result is a JS object // Do something with the result here } });

One key to flexibility within JavaScript framework is "dictionaries" or "property bags", allowing for adding, removing, and modifying of existing properties.  Thanks to Dojo's use of dojo.contentHandlers and dojo.xhr's handleAs property, you can handle the result of your AJAX requests before they are passed to a callback!

JavaScript框架中灵活性的一个关键是“字典”或“属性包”，它允许添加，删除和修改现有属性。 感谢Dojo使用dojo.contentHandlers和dojo.xhr的handleAs属性，您可以在将AJAX请求的结果传递给回调之前对其进行处理！

翻译自: https://davidwalsh.name/dojo-xhr-handleas

dojo ajax 传参

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