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 import pnews.HTML;
  26
  27 public class Pnews extends HttpServlet {
  28         private static final Logger LOG = Logger.getLogger(Pnews.class.getName());
  29         private static final long serialVersionUID = 1L;
  30         private static final ArticleProvider provider = ArticleProvider.singleton;
  31
  32         private static String getQueryParameter(HttpServletRequest rq, String key)
  33                         throws UnsupportedEncodingException {
  34                 String[] params;
  35                 int idx;
  36                 String q;
  37
  38                 q = rq.getQueryString();
  39
  40                 if (q == null)
  41                         return null;
  42
  43                 params = URLDecoder.decode(q, "UTF-8").split("&");
  44
  45                 for (String p: params) {
  46                         idx = p.indexOf('=');
  47
  48                         if (idx > 1 && p.substring(0, idx).equals(key))
  49                                 return p.substring(idx + 1);
  50                 }
  51
  52                 return null;
  53         }
  54
  55         private static void redirect(HttpServletRequest rq, HttpServletResponse rp) {
  56                 String redirectURL;
  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                                 rp.setHeader("Location", redirectURL);
  67                                 rp.setStatus(HttpServletResponse.SC_TEMPORARY_REDIRECT);
  68                         } else {
  69                                 LOG.severe("No redirection URL");
  70                                 rp.setStatus(HttpServletResponse.SC_NOT_FOUND);
  71                         }
  72
  73                 } catch (UnsupportedEncodingException e) {
  74                         e.printStackTrace();
  75                         LOG.log(Level.SEVERE, "redirect failure", e);
  76                         rp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
  77                 }
  78
  79                 LOG.exiting(Pnews.class.getName(), "redirect");
  80         }
  81
  82         private void writeArticles(Category cat, HttpServletResponse rp) {
  83                 String html;
  84                 List<Article> articles;
  85
  86                 try {
  87                         articles = provider.getArticles(cat);
  88                         if (articles != null) {
  89                                 html = HTML.toHTML(articles, cat);
  90                                 rp.setContentType("text/html");
  91                                 rp.getWriter().write(html);
  92                         } else {
  93                                 LOG.severe("writeArticles cannot retrieve any articles");
  94                                 html = HTML.toHTML(new ArrayList<Article>(), cat);
  95                                 rp.setContentType("text/html");
  96                                 rp.getWriter().write(html);
  97                         }
  98                 } catch (IOException | IllegalArgumentException | FeedException e) {
  99                         LOG.log(Level.SEVERE, "writeArticles failure", e);
 100                         rp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
 101                 }
 102         }
 103
 104         private void copy(InputStream in, Writer writer) throws IOException {
 105                 Reader r;
 106                 char[] buf;
 107                 int n;
 108
 109                 buf = new char[1024];
 110                 r = new InputStreamReader(in);
 111                 while ( (n = r.read(buf, 0, buf.length)) != -1)
 112                         writer.write(buf, 0, n);
 113         }
 114
 115         @Override
 116         protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
 117                 String path;
 118                 InputStream in;
 119
 120                 LOG.info("doGet " + req.getRequestURI());
 121
 122                 path = req.getPathInfo();
 123
 124                 if (path.equals("/redirect")) {
 125                         redirect(req, resp);
 126                         return ;
 127                 }
 128
 129                 if (path.equals("/style.css")) {
 130                         try {
 131                                 in = HTML.class.getClassLoader().getResourceAsStream("style.css");
 132                                 copy(in, resp.getWriter());
 133                                 resp.setContentType("text/css");
 134
 135                                 return ;
 136                         } catch (IOException e) {
 137                                 LOG.log(Level.SEVERE, "doGet failure", e);
 138                                 resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
 139
 140                                 return ;
 141                         }
 142                 }
 143
 144                 if (path.equals("/")) {
 145                         writeArticles(Category.TOP, resp);
 146                         return ;
 147                 }
 148
 149                 for (Category cat: Category.values()) {
 150                         if (path.equals('/' + cat.getId())) {
 151                                 writeArticles(cat, resp);
 152                                 return ;
 153                         }
 154                 }
 155
 156                 try {
 157                         resp.getWriter().write("Not found " + req.getPathInfo());
 158                         resp.setStatus(HttpServletResponse.SC_NOT_FOUND);
 159                 } catch (IOException e) {
 160                         LOG.log(Level.SEVERE, "doGet failure", e);
 161                         resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
 162                 }
 163         }
 164
 165         @Override
 166         public void init(ServletConfig config) throws ServletException {
 167                 LOG.info("Pnews servlet init " + config.getServletContext().getContextPath());
 168
 169         }
 170 }