Question

我正在使用angular来制作与API REST通信的用户界面。在波纹管功能中，我首先通过发布请求添加项目，然后在表单中添加用户输入的别名列表，然后将别名添加到项目中，然后获取所选应用程序的列表，然后寻找然后将其ID添加到项目中。在帖子下方调用：

addProject(name: string, description: string): void {

    // Ajouter un nouveau projet
    let newProjectId: number;
    let newAliasId: number;
    let url = this.baseUrl + "/projects";
    this.httpClient.post<Project>(url,
        {'name': name, 'description': description }, 
        httpOptions).subscribe((data: any) => { newProjectId = data['result']['id'];})

    // Ajouter les alias 
    for (let entry of this.aliasList) {
        let UrlAddAlias = this.baseUrl + "/alias";
        this.httpClient.post(UrlAddAlias, {'alias': entry }, httpOptions)
        .subscribe((data: any) => { newAliasId = data['result']['id'];});
        // Ajouter les alias au nouveau projet
        let UrlAliasToProject = this.baseUrl + `/projects/${newProjectId}/alias`;
        this.httpClient.post(UrlAliasToProject, {"alias_id" : newAliasId}, httpOptions)
        .subscribe((data: any) => { console.log("alias added to project");});
    };

    // Ajouter les applications selectionnées au nouveau projet
    for (let entry of this.selectedApps) {
        let Urlapp = this.baseUrl + `/apps/name/${entry}`;
        let appId;
        this.httpClient.get(Urlapp).subscribe(data => { appId = data['result']['id']; });
        let urlappToProject = this.baseUrl + `/projects/${newProjectId}/apps`;
        this.httpClient.post(urlappToProject, {'app_id': appId });
    };
}

问题是我无法获取newProjectId值和newAliasId值。我收到此错误：

Object { headers: {…}, status: 405, statusText: "Method Not Allowed", url: "http://api.com/v1/projects/undefined/alias", ok: false, name: "HttpErrorResponse", message: "Http failure response for http://api.com/v1/projects/undefined/alias: 405 Method Not Allowed", error: "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 3.2 Final//EN\">\n<title>405 Method Not Allowed</title>\n<h1>Method Not Allowed</h1>\n<p>The method is not allowed for the requested URL.</p>\n" }

我可以通过console.log获取值，但它们在其他地方为undefined。

Answer 1

.subscribe回调异步发生。这意味着在其之后编写的代码仍将在其之前执行...类似于setTimeout

setTimeout(() => console.log('second'));
console.log('first');

基本上，您可以将所有内容放在.subscribe内的.subscribe之后：

.subscribe((data: any) => {
  newProjectId = data['result']['id'];

  for (let entry of this.aliasList) { ...
});

如果可能，您可能还希望重新设计API，以不必发出多个请求并让post自己处理所有事情。

获取Angular 6中POST请求的响应

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