war/src/main/java/pnews/servlet/Pnews.java

   1 package pnews.servlet;
   2
   3 import java.io.IOException;
   4 import java.io.InputStream;
   5 import java.io.InputStreamReader;
   6 import java.io.Reader;
   7 import java.io.UnsupportedEncodingException;
   8 import java.io.Writer;
   9 import java.net.URLDecoder;
  10 import java.util.ArrayList;
  11 import java.util.List;
  12 import java.util.logging.Level;
  13 import java.util.logging.Logger;
  14
  15 import javax.servlet.ServletConfig;
  16 import javax.servlet.ServletException;
  17 import javax.servlet.http.HttpServlet;
  18 import javax.servlet.http.HttpServletRequest;
  19 import javax.servlet.http.HttpServletResponse;
  20
  21 import com.rometools.rome.io.FeedException;
  22
  23 import pnews.Article;
  24 import pnews.Category;
  25
  26 public class Pnews extends HttpServlet {
  27         private static final Logger LOG = Logger.getLogger(Pnews.class.getName());
  28         private static final long serialVersionUID = 1L;
  29         private static final ArticleProvider provider = ArticleProvider.singleton;
  30
  31         private static String getQueryParameter(HttpServletRequest rq, String key)
  32                         throws UnsupportedEncodingException {
  33                 String[] params;
  34                 int idx;
  35                 String q;
  36
  37                 q = rq.getQueryString();
  38
  39                 if (q == null)
  40                         return null;
  41
  42                 params = URLDecoder.decode(q, "UTF-8").split("&");
  43
  44                 for (String p: params) {
  45                         idx = p.indexOf('=');
  46
  47                         if (idx > 1 && p.substring(0, idx).equals(key))
  48                                 return p.substring(idx + 1);
  49                 }
  50
  51                 return null;
  52         }
  53
  54         private static void redirect(HttpServletRequest rq, HttpServletResponse rp) {
  55                 String redirectURL;
  56                 Article a;
  57
  58                 LOG.entering(Pnews.class.getName(), "redirect");
  59
  60                 try {
  61                         redirectURL = getQueryParameter(rq, "url");
  62
  63                         LOG.info("Request redirection to " + redirectURL);
  64
  65                         if (redirectURL != null) {
  66                                 a = ArticleStore.singleton.get(redirectURL);
  67                                 if (a != null)
  68                                         a.readCount.incrementAndGet();
  69                                 else
  70                                         LOG.severe("Cannot find the article " + redirectURL);
  71
  72                                 rp.setHeader("Location", redirectURL);
  73                                 rp.setStatus(HttpServletResponse.SC_TEMPORARY_REDIRECT);
  74                         } else {
  75                                 LOG.severe("No redirection URL");
  76                                 rp.setStatus(HttpServletResponse.SC_NOT_FOUND);
  77                         }
  78
  79                 } catch (UnsupportedEncodingException e) {
  80                         e.printStackTrace();
  81                         LOG.log(Level.SEVERE, "redirect failure", e);
  82                         rp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
  83                 }
  84
  85                 LOG.exiting(Pnews.class.getName(), "redirect");
  86         }
  87
  88         private void writeStats(HttpServletResponse rp) throws IOException {
  89                 rp.setContentType("application/json;charset=utf-8");
  90                 rp.setCharacterEncoding("utf-8");
  91
  92                 rp.getWriter().write(JSON.getStats());
  93         }
  94
  95
  96         private void writeArticles(Category cat, HttpServletResponse rp) {
  97                 String html;
  98                 List<Article> articles;
  99
 100                 try {
 101                         articles = provider.getArticles(cat);
 102                         if (articles != null) {
 103                                 html = HTML.toHTML(articles, cat);
 104                                 rp.setContentType("text/html;charset=utf-8");
 105                                 rp.getWriter().write(html);
 106                                 rp.setCharacterEncoding("utf-8");
 107                         } else {
 108                                 LOG.severe("writeArticles cannot retrieve any articles");
 109                                 html = HTML.toHTML(new ArrayList<Article>(), cat);
 110                                 rp.setContentType("text/html");
 111                                 rp.getWriter().write(html);
 112                         }
 113                 } catch (IOException | IllegalArgumentException | FeedException e) {
 114                         LOG.log(Level.SEVERE, "writeArticles failure", e);
 115                         rp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
 116                 }
 117         }
 118
 119         private void copy(InputStream in, Writer writer) throws IOException {
 120                 Reader r;
 121                 char[] buf;
 122                 int n;
 123
 124                 buf = new char[1024];
 125                 r = new InputStreamReader(in);
 126                 while ( (n = r.read(buf, 0, buf.length)) != -1)
 127                         writer.write(buf, 0, n);
 128         }
 129
 130         @Override
 131         protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
 132                 final String METHOD_NAME = "doGet";
 133                 String path;
 134                 InputStream in;
 135
 136                 RequesterLog.singleton.writeRequest(req);
 137
 138                 LOG.info("doGet " + req.getRemoteAddr().toString() + " " + req.getRequestURI() + " " + req.getQueryString());
 139
 140                 LOG.info(METHOD_NAME + " queryString=" + req.getQueryString());
 141
 142                 path = req.getPathInfo();
 143
 144                 if (path.equals("/redirect")) {
 145                         redirect(req, resp);
 146                         return ;
 147                 }
 148
 149                 if (path.equals("/style.css")) {
 150                         try {
 151                                 in = HTML.class.getClassLoader().getResourceAsStream("style.css");
 152                                 copy(in, resp.getWriter());
 153                                 resp.setContentType("text/css");
 154
 155                                 return ;
 156                         } catch (IOException e) {
 157                                 LOG.log(Level.SEVERE, "doGet failure", e);
 158                                 resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
 159
 160                                 return ;
 161                         }
 162                 }
 163
 164                 if (path.equals("/")) {
 165                         writeArticles(Category.TOP, resp);
 166                         return ;
 167                 }
 168
 169                 try {
 170
 171                         if (path.equals("/stats")) {
 172                                 writeStats(resp);
 173                                 return ;
 174                         }
 175
 176                         for (Category cat: Category.values()) {
 177                                 if (path.equals('/' + cat.getId())) {
 178                                         writeArticles(cat, resp);
 179                                         return ;
 180                                 }
 181                         }
 182
 183                         resp.getWriter().write("Not found " + req.getPathInfo());
 184                         resp.setStatus(HttpServletResponse.SC_NOT_FOUND);
 185                 } catch (IOException e) {
 186                         LOG.log(Level.SEVERE, "doGet failure", e);
 187                         resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
 188                 }
 189         }
 190
 191         @Override
 192         public void init(ServletConfig config) throws ServletException {
 193                 LOG.info("Pnews servlet init " + config.getServletContext().getContextPath());
 194
 195         }
 196 }