如何在 Mozilla 附加 SDK 扩展中将变量传递给请求 API？

Question

我正在尝试将变量值传递给 Mozilla Add-on SDK 扩展的 Request API。

在下面的代码中，fetch Request 有效。但是，当我尝试在 onCompletion 处理程序中为 fetch 请求另一个 Request (assign) 时，它说：

RequirementError: The option "url" is invalid.

如何使用 onCompletion 处理程序中的 URL 用于 fetch Request 用于 assign 中的 URL Request?

var fetch = Request({
    url: 'http://itildemo.servicedeskplus.com/sdpapi/request?INPUT_DATA={%22operation%22:{%22details%22:{%22status%22:%22open%22,%22from%22:0,%22limit%22:500,%22filterby%22:%22Unassigned_System%22}}}&OPERATION_NAME=GET_REQUESTS&TECHNICIAN_KEY=07109ADB-E642-4F46-917C-CA60F89CE6DC&format=json',
    overrideMimeType: "text/plain; charset=latin1",
    onComplete: function (response) {
        workorder_id=JSON.parse(response.text).operation.details;
        if(workorder_id!=null){
            assignurl=urls.URL('http://itildemo.servicedeskplus.com/sdpapi/request/'+workorder_id[0].WORKORDERID+'?OPERATION_NAME=EDIT_REQUEST&TECHNICIAN_KEY=07109ADB-E642-4F46-917C-CA60F89CE6DC&INPUT_DATA= <Details><parameter><name>technician</name><value>'+technician_id[0].NAME+'</value></parameter></Details>');
            console.log(assignurl);
            assign.get();}
        else{fetch.get();}
    }
});

var assign = Request({
    url: assignurl,
    overrideMimeType: "text/plain; charset=latin1",
    onComplete: function (response) {
          var o=technician_id[0];
          for (var k = 0; k < technician_id.length; k++) {
              if (technician_id.length - 1 == k) {
                  technician_id[k] = o;
              } else {
                  technician_id[k] = technician_id[k + 1];
              };
          };
          fetch.get();
    }
});

Answer 1

您对异步代码的执行顺序感到困惑。

如上所写，

var assign = Request({
    url: assignurl,

在回调函数执行提供 assignurl:

的行之前执行

assignurl=urls.URL('http:// ...

通过调用 Request() constructor，(var assign = Request({)，您已将 url 分配给当时存在的 assignurl。在该点之后更改变量 assignurl 对 assign Request 没有影响。因此，您要么需要更改 assign.url，要么在 URL 可用后创建请求。

注意： 在调用 Request 构造函数时，url 参数必须存在且有效。因此，我假设您的问题在陈述错误时是不正确的：

RequirementError: The option "url" is invalid.

仅在 fetch 的 onCompletion 处理程序中发生。当您使用无效的 assignurl.

执行 var assign = Request({url:asignurl 时应该会发生这种情况

您可以通过多种方式更改代码以在 Request 中使用您现在拥有的 URL（通过 fetch onComplete 回调）您正在为 assign 创建。使用哪种方法取决于您是否要在代码中的多个位置使用与 assign 非常相似的请求。

一个可能的更改是将 assign Request 的创建移动到 fetch 的 onCompletion 处理程序中：

var Request = require("sdk/request").Request;
var assignurl;          //Unknown from Question
var technician_id=[];   //Unknown from Question
var workorder_id;       //Unknown from Question

var assign;
var fetch = Request({
    url: 'http://itildemo.servicedeskplus.com/sdpapi/request?INPUT_DATA={%22operation%22:{%22details%22:{%22status%22:%22open%22,%22from%22:0,%22limit%22:500,%22filterby%22:%22Unassigned_System%22}}}&OPERATION_NAME=GET_REQUESTS&TECHNICIAN_KEY=07109ADB-E642-4F46-917C-CA60F89CE6DC&format=json',
    overrideMimeType: "text/plain; charset=latin1",
    onComplete: function (response) {
        workorder_id=JSON.parse(response.text).operation.details;
        if(workorder_id!=null){
            assignurl=urls.URL('http://itildemo.servicedeskplus.com/sdpapi/request/'+workorder_id[0].WORKORDERID+'?OPERATION_NAME=EDIT_REQUEST&TECHNICIAN_KEY=07109ADB-E642-4F46-917C-CA60F89CE6DC&INPUT_DATA= <Details><parameter><name>technician</name><value>'+technician_id[0].NAME+'</value></parameter></Details>');
            assign = Request({
                url: assignurl,
                overrideMimeType: "text/plain; charset=latin1",
                onComplete: function (response) {
                    var o=technician_id[0];
                    for (var k = 0; k < technician_id.length; k++) {
                        if (technician_id.length - 1 == k) {
                            technician_id[k] = o;
                        } else {
                            technician_id[k] = technician_id[k + 1];
                        };
                    };
                    fetch.get(); //This will throw an error (see below).  Even if it
                                 //  worked it is recursive, which is probably not
                                 //  what you desire.
                }
            });
            console.log(assign.url);
            assign.get();}
        else{
            fetch.get(); //This should always throw an error as you are attempting to
                         //  re-use the Request. In other words, the only way to get
                         //  here is if you have already done fetch.get() once
                         //  and reusing the Request throws an error. 
        }
    }
});

如果您可能会发出多个 assign 请求，您可以构建代码，以便创建 assign Request 封装在一个 function 中，您可以调用多个多次创建多个非常相似的请求，如果您需要在代码的其他地方这样做：

var Request = require("sdk/request").Request;
var technician_id=[];   //Unknown from Question
var workorder_id;       //Unknown from Question

var assign;
var fetch = Request({
    url: 'http://itildemo.servicedeskplus.com/sdpapi/request?INPUT_DATA={%22operation%22:{%22details%22:{%22status%22:%22open%22,%22from%22:0,%22limit%22:500,%22filterby%22:%22Unassigned_System%22}}}&OPERATION_NAME=GET_REQUESTS&TECHNICIAN_KEY=07109ADB-E642-4F46-917C-CA60F89CE6DC&format=json',
    overrideMimeType: "text/plain; charset=latin1",
    onComplete: function (response) {
        workorder_id=JSON.parse(response.text).operation.details;
        if(workorder_id!=null){
            assign = setupAssignRequest(urls.URL('http://itildemo.servicedeskplus.com/sdpapi/request/'+workorder_id[0].WORKORDERID+'?OPERATION_NAME=EDIT_REQUEST&TECHNICIAN_KEY=07109ADB-E642-4F46-917C-CA60F89CE6DC&INPUT_DATA= <Details><parameter><name>technician</name><value>'+technician_id[0].NAME+'</value></parameter></Details>'));
            console.log(assign.url);
            assign.get();}
        else{
            fetch.get(); //As stated above, this should always throw an error.
        }
    }
});

function setupAssignRequest(assignurl) {
    return Request({
        url: assignurl,
        overrideMimeType: "text/plain; charset=latin1",
        onComplete: function (response) {
            var o=technician_id[0];
            for (var k = 0; k < technician_id.length; k++) {
                if (technician_id.length - 1 == k) {
                    technician_id[k] = o;
                } else {
                    technician_id[k] = technician_id[k + 1];
                };
            };
            fetch.get(); //If the only code you have is what is shown, this will
                         // throw an error. It is possible that "fetch" has been 
                         // re-initialized with a new call to Request elsewhere
                         // in your code.
        }
    });
}

关于 fetch 的 onComplete 处理程序中的 fetch.get();：尝试这样做应该总是导致抛出错误。获得该代码的唯一方法是已经调用 fetch.get(); 和 each Request can only be used once:

Each Request object is designed to be used once. Attempts to reuse them will throw an error.

如何在 Mozilla 附加 SDK 扩展中将变量传递给请求 API？

How to pass Variable to Request API in Mozilla Add-on SDK extension?

javascript

mozilla

firefox-addon