哪种设计模式适合以下 API 实现?

Question

我想向我的网站添加oEmbed 标签(我是 oEmbed api 提供商(。我的 api 应该根据文件类型响应结果。

o嵌入类型具有

• 相片
• 视频
• 链接
• 富

我对照片的回复包含以下字段

{
"author_name": "rajasuba.s",
"author_url": <author_image_url>,
"thumbnail_width": 130,
"provider_url": <provider_url>,
"thumbnail_url": "<thumbnail_image_url>",
"title": "Picture.png",
"provider_name": "XYZ",
"type": "photo",
"version": "1.0",
"url": "<given_url>",
"thumbnail_height": 120
}

我对视频的回复包含以下字段

{
"author_name": "rajasuba.s ",
"author_url": "<image_url_of_author>",
"thumbnail_width": 130,
"html": "<iframe src="<source_url>" width="480" height="270" frameborder="0">",
"provider_url": "<service_url>",
"thumbnail_url": "<thumbnail_image_url>",
"title": "video_small_resource.mp4",
"provider_name": "XYZ",
"type": "video",
"version": "1.0",
"thumbnail_height": 120
}

链接和丰富类型也是如此。

我通过以下方式实现此 api。我所拥有的只是一个servlet(api请求到达的地方(。在这里我有以下内容

public class OEmbedServlet extends HttpServlet {
public void service(HttpServletRequest request, HttpServletResponse response) throws IOException
{
//Parse request uri
String format = request.getParameter(“format”);
String url = request.getParameter(“url”);
String file_id = request.getParameter(“file_id”);
String max_width = request.getParameter(“max_height”);
String max_height = request.getParameter(“max_width”);
if(authorised_user) {
oembed.setFileInfo(file_id);
oembed.setProviderInfo();
oembed.setURL(url);
oembed.setThumbnailInfo();
oembed.setOEmbedType();
}
writeResponse(response, oembed.getJSONObject(), format);
}
}

另一个类为这个servlet做所有实用程序工作

public class OEmbed {
private HttpServletRequest request;
public OEmbed(HttpServletRequest request) {
this.request = request;
this.oembedType = OEmbedType.LINK;
this.width = 0;
this.height = 0;
this.thumbnailWidth = 0;
this.thumbnailHeight = 0;
}
public enum OEmbedType {
RICH/*0*/,
LINK/*1*/,
PHOTO/*2*/,
VIDEO/*3*/
}
public void String author;
public void String file_id;
public void String extension;
public void String fileType;
//Getter and setter methods for all required info to be passed in the response like 
public String getAuthorName() {
return this.author;
}
public String setAuthorName(String name) {
this.author = name;
}
public void setURL(String url) {
this.url = url;
}
public String getURL(String url) {
return this.url;
}
//…. and other getter and setter methods
/*
- Few setter methods are invoked from the servlet
- Few setter methods are clubbed together and invoked from util classes
- The setter methods in util does some computation to assign value - or they are assigned based on inputted params
- All required getter methods are obtained while writing response json
*/
public JSONObject getJSONObject(boolean isAuthorised) throws Exception
{
JSONObject oembedObj = new JSONObject();
if(this.url != null && !this.url.isEmpty()) {
switch(this.oembedType) {
case PHOTO:
oembedObj.put("url", this.thumbnailUrl);
break;
case LINK:
oembedObj.put("url", this.url);
default:
oembedObj.put("url", this.url);
oembedObj.put("html", htmlContent);
break;
}
if(this.thumbnailUrl != null && !this.thumbnailUrl.isEmpty()) {
oembedObj.put(“thumbnail_url”, this.thumbnailUrl);
oembedObj.put(“thumbnail_width”, this.thumbnailWidth);
oembedObj.put(“thumbnail_height”, this.thumbnailHeight);
}
}
}

我仍然觉得这个设计很麻烦。我在以下事情上感到不方便，

• 很少有 setter 方法从 servlet 调用，很少从 util 类调用
• 同样在util类中使用类变量时 - 我必须小心这些属性值是否已经初始化

举个例子

public void setThubnailUrl(String url) {
this.thumbnail_url = url;
}
public void setThubnailUrl() {
setThumbnailInfo();
getThumbnailStatus();
setThumbnailUrl(url);    //So before initialising this url - i have to make sure manually - whether the required params for thumbnail url is initialised already (I'm not sure weather it is a best practice to do like this)
}

我怎样才能更好地组织它？哪种设计模式适合以下情况？欢迎任何建议：-(

Answer 1

首先，您现在将标头和内容烘焙到单个消息中，这使得在客户端和服务器上都更难处理。

将消息分为两部分。

标头描述常规元数据，例如作者、生成器服务和内容类型。每个内容类型的内容都不同。

通过执行这种小分离，您可以自由创建不同的内容构建器，而不会影响常规处理程序。

因此，您可以引入该部分的工厂模式，并让不同的类生成不同的内容。

因为我是.NET编码员，所以我不能给你代码。但通常您有一个哈希映射，其中键是 contentType，值是创建内容的类的因子方法。

伪代码：

var classInstance = _factoryMap[requestedContentType].CreateInstance();
var content = classInstance.CreateContent(someResourceId);
//create response here.