我尝试在Meteor 1.3.2.4中使用request npm package作为同步。
根据this Meteor guide article,我首先尝试使用Meteor.bindEnvironment
,如下所示:
import request from 'request';
let result = {success: false, error: null, content: ""};
let requestOptions = {
url: <MY-URL-HERE>
};
request(requestOptions, Meteor.bindEnvironment((error, response, html) => {
if (!error && response.statusCode == 200) {
result.success = true;
result.content = html;
result.error = null;
}
else {
result.success = false;
result.content = "";
result.error = error;
}
}));
但似乎仍然是异步电话。
在下一步中,我尝试在meteor论坛上使用基于this answer的Meteor.wrapAsync
,这是下一个尝试代码:
import request from 'request';
let result = {success: false, error: null, content: ""};
let requestOptions = {
url: <MY-URL-HERE>
};
let func = function (options, callback) {
request(options, function (error, response, body) {
console.log("error: " + JSON.stringify(error));
console.log("response: " + JSON.stringify(response));
console.log("body: " + JSON.stringify(body));
callback(error, {response, body});
});
};
let {error, response, body} = syncRequest(requestOptions);
console.log("error2: " + JSON.stringify(error));
console.log("response2: " + JSON.stringify(response));
console.log("body2: " + JSON.stringify(body));
if (response.statusCode == 200) {
result.success = true;
result.content = body;
result.error = null;
}
else {
result.success = false;
result.content = "";
result.error = error;
}
除了请求包含错误外,此代码工作正常。当请求包含错误(例如url不正确)时,这会中断以下异常:
I20160518-08:24:22.180(4.5)? error: {}
I20160518-08:24:22.181(4.5)? response: undefined
I20160518-08:24:22.182(4.5)? body: undefined
W20160518-08:24:22.839(4.5)? (STDERR) TypeError: The header content contains invalid characters
W20160518-08:24:22.839(4.5)? (STDERR) at Object.Future.wait (/home/cyc/.meteor/packages/meteor-tool/.1.3.2_4.7bk6xv++os.linux.x86_64+web.browser+web.cordova/mt-os.linux.x86_64/dev_bundle/server-lib/node_modules/fibers/future.js:420:15)
W20160518-08:24:22.839(4.5)? (STDERR) at packages/meteor/helpers.js:119:1
W20160518-08:24:22.839(4.5)? (STDERR) at Object.getContent (server/lib/get_content.js:51:26)
W20160518-08:24:22.839(4.5)? (STDERR) at Object.fetch (server/lib/get_content.js:205:27)
W20160518-08:24:22.839(4.5)? (STDERR) at Object.fetchSource (server/lib/get_content.js:369:31)
W20160518-08:24:22.840(4.5)? (STDERR) at [object Object].action (server/controller/postsController.js:79:39)
W20160518-08:24:22.840(4.5)? (STDERR) at [object Object].handle (packages/iron_middleware-stack/lib/handler.js:74:1)
W20160518-08:24:22.840(4.5)? (STDERR) at boundNext (packages/iron_middleware-stack/lib/middleware_stack.js:251:1)
W20160518-08:24:22.840(4.5)? (STDERR) at runWithEnvironment (packages/meteor/dynamics_nodejs.js:110:1)
W20160518-08:24:22.840(4.5)? (STDERR) at packages/meteor/dynamics_nodejs.js:123:1
W20160518-08:24:22.840(4.5)? (STDERR) - - - - -
W20160518-08:24:22.840(4.5)? (STDERR) at ClientRequest.OutgoingMessage.setHeader (http.js:733:13)
W20160518-08:24:22.840(4.5)? (STDERR) at new ClientRequest (http.js:1429:14)
W20160518-08:24:22.840(4.5)? (STDERR) at Object.exports.request (http.js:1899:10)
W20160518-08:24:22.841(4.5)? (STDERR) at Request.start (/home/cyc/Programming/Projects/content/Sources/node_modules/request/request.js:753:32)
W20160518-08:24:22.841(4.5)? (STDERR) at Request.end (/home/cyc/Programming/Projects/content/Sources/node_modules/request/request.js:1418:10)
W20160518-08:24:22.841(4.5)? (STDERR) at end (/home/cyc/Programming/Projects/content/Sources/node_modules/request/request.js:580:14)
W20160518-08:24:22.841(4.5)? (STDERR) at Object._onImmediate (/home/cyc/Programming/Projects/content/Sources/node_modules/request/request.js:594:7)
W20160518-08:24:22.841(4.5)? (STDERR) at processImmediate [as _immediateCallback] (timers.js:363:15)
现在我有两个问题:
答案 0 :(得分:2)
Meteor.bindEnvironment
只需确保在调用原始函数时使用的上下文中调用回调。它不应该使您的代码看起来是同步的。如果您没有使用它,您的回调将不会在光纤内运行(这将阻止您执行某些操作)并且您将无法访问某些变量(例如当前用户)。 Crhis Mather有一个excellent video关于这个主题(请记住,有些代码有点过时,但核心仍然有效)。
Meteor.wrapAsync
包含期望使用标准的error-first 2 arguments签名进行回调的函数。由于request
不符合这个确切的标准(它使用带有3个参数的回调),因此论坛帖子建议用一个函数来包装它,该函数需要使用前面提到的2个参数进行回调。
约定是调用“wrapped”函数的结果是传递给回调的第二个参数的值(data
),如果有的话会抛出错误。
因此,就像现在一样,您可以使用try..catch
块包装函数并查看是否存在错误。
另一个选择是永远不会引发错误:
let func = function (options, callback) {
request(options, function (error, response, body) {
callback(null, {response, body, error});
});
};
这将始终生成{response, body, error}
个对象,如果没有错误,error
将为null
。
我认为http包非常有效,并且使用便捷方法(例如,一般call
,特定get
和{{1}对您来说几乎完全相同}):
例如:
post