javascript - Angular 2 - 链接 Web 服务调用

Question

我试图连续进行几个 Web 服务调用，但我遇到的问题是第二次调用将在 .subscribe 在第一次调用执行之前进行。我需要 .subscribe 发生才能设置 this.saveValue，因为 this.saveValue 是在第二次 Web 服务调用的 JSON 中传递的。

此代码当前发生的情况是将进行第一次调用，然后进行第二次调用，然后设置 saveValue。

组件.ts

busy: Subscription;
saveValue: string;

submitButton_Click():void{
    try{
        // First Web Service Call
        this.busy = this.service.firstMethod(this.object)
            .first()
            .subscribe(result => {
                if(result.length > 0){
                    this.saveValue= result; // VALUE SET FOR USE OF NEXT WEB SERVICE CALL
                    console.log('Worked');
                }
                else{
                    console.log('Failed');
                }     
            })



        for(let current of this.array){
            let temp= new Object();
            temp.id = this.saveValue;

            // Second Web Service Call
            this.busy = this.service.secondMethod(temp)
                .first()
                .subscribe(result => {
                    if(result.valueOf() != false){
                        console.log('Worked');
                    }
                    else{
                        console.log('Failed');
                    }          
                })
         }

服务.ts

// First Method
public firstMethod(object: Object): Observable<string>{
    return this.client.post<Result>(URL + '/add', object, new Result(), this.token.id)
        .map(result => {
            let temp = new Object().deserialize(result.data);
            return temp.id;
        }, this)
        .catch(this.handleError);
}  // This works and returns proper value

// Second Method (Needs this.saveValue as part of the passed object)
public secondMethod(object: Object): Observable<boolean> {
    return this.client.post<Result>(OTHERURL + '/add', object, new Result(), this.token.id)
        .map(result => result.success, this)
        .catch(this.handleError);
}

感谢您的帮助!

Answer 1

是的，因为您必须等待第一个完成。任何时候你进行异步调用，执行都会愉快地继续下一段代码。像这样尝试:

this.busy = this.service.firstMethod(this.object)
            .first()
            .subscribe(result => {
                if(result.length > 0){
                    this.saveValue= result; // VALUE SET FOR USE OF NEXT WEB SERVICE CALL
                    console.log('Worked');

            for(let current of this.array){
            let temp= new Object();
            temp.id = this.saveValue;

            // Second Web Service Call
            this.busy = this.service.secondMethod(temp)
                .first()
                .subscribe(result => {
                    if(result.valueOf() != false){
                        console.log('Worked');
                    }
                    else{
                        console.log('Failed');
                    }          
                })
         }
                }
                else{
                    console.log('Failed');
                }     
            })

抱歉格式垃圾；我手边没有 WebStorm，没有它我很懒:-)