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建立關閉this question ...我希望能夠返回帳戶時間軸的最後5條推文以及它們可能附加的任何圖像。我的問題是，在對Twitter的API進行搜索調用時，某些返回的推文JSON根本不包含entities.media.media_url鍵。如果我將entities.media.media_url作爲調用的一部分包含進去，並且tweet不包含任何附件，它將打破整個請求，並且根本不會呈現任何推文。在呈現請求之前是否可以檢查推文是否包含該信息？例如，在試圖解析這兩個微博：Angular4 - 如何檢查Twitter媒體密鑰是否存在或未定義
tweet1（無圖）
...
"created_at":"Tue Aug 29 17:30:29 +0000 2017"
"entities": {
"hashtags": [{...},{...}],
"symbols": [],
...
},
"metadata":{...},
"user": {...},
...
}
tweet2（包含一個附加的圖像）
...
"created_at":"Mon Aug 28 12:30:31 +0000 2017"
"entities": {
"hashtags": [{...},{...}],
"media":[ {"id":..., "id_str":"...", ..., "media_url": "...",
"media_url_https": "..."]
"symbols": [],
...
},
"metadata":{...},
"user": {...},
...
}
我有一個Node.js的後端處理最（下面的this tutorial）， 和我的tweets.component.ts獲取元素並將它們分配給要在前端插值的變量。
tweets.component.ts
import { Component, OnInit, Input } from '@angular/core';
import { NO_ERRORS_SCHEMA } from '@angular/core';
import { Ng4TwitterTimelineModule } from 'ng4-twitter-timeline/lib/index';
import { Ng4TwitterTimelineService } from 'ng4-twitter-timeline/lib/index';
import { Http, Headers } from '@angular/http';
import { NgModel, NgForm, FormsModule } from '@angular/forms';
@Component({
selector: 'app-tweets',
templateUrl: './tweets.component.html',
styleUrls: ['./tweets.component.scss'],
})
export class TweetsComponent implements OnInit {
searchquery = 'musechat';
tweetsdata;
screen_name;
user;
profile_img_url;
user_id;
asset_img_url;
// icon = this.tweetsdata[0].user.entities.profile_image_url;
constructor (private http: Http) {}
ngOnInit() {
this.makecall();
this.searchcall();
}
makecall() {
const headers = new Headers();
headers.append('Content-Type', 'application/X-www-form-urlencoded');
this.http.post('http://localhost:3000/authorize', {headers: headers}).subscribe((res) => {
// console.log(res);
});
}
searchcall() {
const headers = new Headers();
// const searchterm = 'query=' + this.searchquery;
const searchterm = 'query=from%3Adailymuse%20%23' + this.searchquery;
headers.append('Content-Type', 'application/X-www-form-urlencoded');
this.http.post('http://localhost:3000/search', searchterm, {headers: headers}).subscribe((res) => {
this.tweetsdata = [
res.json().data.statuses[0],
res.json().data.statuses[1],
res.json().data.statuses[2],
res.json().data.statuses[3],
res.json().data.statuses[4],
// res.json().data.statuses[5],
];
console.log(this.tweetsdata);
this.screen_name = this.tweetsdata[0].user.screen_name;
this.user = this.tweetsdata[0].user.name;
this.profile_img_url = this.tweetsdata[0].user.profile_image_url_https;
this.user_id = this.tweetsdata[0].user.id_str;
});
}
}
}
tweets.component.html
<div class="twitter-container">
<div class="twitter-carousel">
<div class="twitter-header">
<a class="tw-header" href="http://twitter.com/intent/user?user_id={{user_id}}" target="_blank">
<img class="twitter-icon" src={{profile_img_url}}>
<span>{{user}}</span>
<span class="twitter-screen">@{{screen_name}}</span>
</a>
</div>
<hr>
<div class="tweet-container">
<div *ngFor="let item of tweetsdata" class="tweets-card">
<div class="tweet-text">
<p class="tweet-date">{{item.created_at | slice:0:10}}</p>
<p>{{item.text}}</p>
<!-- <div *ngIf="item.entities.media[0].media_url" class="tweet-img"> -->
<!-- <img [src]=item.entities.media[0].media_url/> --> <!-- either of these break the code if there is a tweet that doesn't contain an attached image -->
<div>
<p>{{getImage()}}</p>
</div>
<div class="interact-tweet">
<a href="https://twitter.com/intent/tweet?in_reply_to={{item.id_str}}" target="_blank"><i class="fa fa-reply" aria-hidden="true"></i></a>
<a href="https://twitter.com/intent/retweet?tweet_id={{item.id_str}}" target="_blank"><i class="fa fa-retweet" aria-hidden="true"></i></a>
<a href="https://twitter.com/intent/like?tweet_id={{item.id_str}}" target="_blank"><i class="fa fa-heart" aria-hidden="true"></i></a>
</div>
</div>
</div>
</div>
</div>
</div>