一方面,我有一个RESTful HAL HATEOAS集合,如下所示:
{
"page": 1,
"limit": 10,
"pages": 18,
"total": 174,
"_links": {
"self": { "href": "/users?page=1&limit=10" },
"first": { "href": "/users?page=1&limit=10" },
"last": { "href": "/users?page=18&limit=10" },
"next": { "href": "/users?page=2&limit=10" }
},
"_embedded": {
"users": [
{
"name": "bob",
"_links": { "self": { "href": "/users/1" } }
},
...
]
}
}
另一方面,我有一个Angular 2应用程序。
public getUsers(uri: string = this.baseURI): Observable<User> {
return this.http.get(uri)
.map(res => res.json()._embedded.users as User[])
.flatMap(d => d) // Transform the flux of arrays in flux of users
.catch(this.handleError);
} // Get only the 10th first users
我尝试做的事情有一个可观察的用户,会在_links.next != null
修改后的服务
public getUsers(uri: string = this.baseURI): Observable<User> {
return this.http.get(uri)
.do(res => {
const uri = JSON.parse(res._body)._links.next.href;
this.nextUri = uri ? uri : null;
})
.map(res => res.json()._embedded.users as User[])
.flatMap(d => d) // Transform the flux of arrays in flux of users
.catch(this.handleError);
}
递归函数
loadAll(uri: string) {
read(uri)
.subscribe(
user => {
this.stockedUsers.push(user);
},
error => console.log(error),
() => {
if (this.nextUri) {
this.loadAll(this.nextUri);
}
}
);
}
有人知道如何正确实现这一目标吗? 我想保留RxJS通量的优势。
UPDATE / ANSWER 傻我!我想我回答了自己。也许这会对其他人有所帮助:
public read(uri: string = this.baseURI): Observable<User> {
return Observable.create(observer => this.iteratePages(observer, uri));
}
private iteratePages(observer: Observer<User>, uri): void {
if (uri == null) { return observer.complete(); }
this.http.get(uri).subscribe(res => {
const data = res.json();
for (const user of data._embedded.users) {
observer.next(user as User);
}
const nextUri = (data._links && data._links.next) ? data._links.next.href : null;
this.iteratePages(observer, nextUri);
});
}