ctbrec-5.3.2-experimental/common/src/main/java/ctbrec/servlet/AbstractDocServlet.java

122 lines
4.5 KiB
Java

package ctbrec.servlet;
import lombok.extern.slf4j.Slf4j;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URL;
import java.net.URLDecoder;
import java.util.*;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import static java.nio.charset.StandardCharsets.UTF_8;
@Slf4j
public abstract class AbstractDocServlet extends HttpServlet {
public static final String CLASSPATH_DIR = "/docs";
private static final Pattern CONTEXT_AWARE_URL = Pattern.compile("@\\{(.*?)\\}");
String loadFile(String resource) throws IOException {
try (InputStream resourceAsStream = getClass().getResourceAsStream(resource)) {
if (resourceAsStream == null) {
throw new FileNotFoundException();
}
var out = new ByteArrayOutputStream();
var length = 0;
var buffer = new byte[1024];
while ((length = resourceAsStream.read(buffer)) >= 0) {
out.write(buffer, 0, length);
}
return out.toString(UTF_8);
}
}
protected String getBaseDir() {
return Optional.ofNullable(getServletContext().getContextPath()).orElse("") + CLASSPATH_DIR;
}
String getHeader() throws IOException {
return renderContextAwareUris(loadFile(CLASSPATH_DIR + "/header.html"));
}
String getFooter() throws IOException {
return renderContextAwareUris(loadFile(CLASSPATH_DIR + "/footer.html"));
}
private String renderContextAwareUris(String s) {
Matcher m = CONTEXT_AWARE_URL.matcher(s);
var contextPath = Optional.ofNullable(getServletContext().getContextPath()).orElse("");
return m.replaceAll(matchResult -> contextPath + matchResult.group(1));
}
List<String> getPages() throws IOException {
List<String> pages = new ArrayList<>();
URL resource = getClass().getResource(CLASSPATH_DIR);
if (Objects.equals(resource.getProtocol(), "file")) {
log.debug("FILE {}", resource);
indexDirectory(resource, pages);
} else if (Objects.equals(resource.getProtocol(), "jar")) {
log.debug("JAR {}", resource);
indexJar(resource, pages);
}
pages.add("index.md");
pages.sort(String::compareToIgnoreCase);
return pages;
}
private void indexJar(URL resource, List<String> pages) throws IOException {
String fileUrl = resource.getFile();
fileUrl = URLDecoder.decode(fileUrl, UTF_8);
int colon = fileUrl.indexOf(':');
int exclamation = fileUrl.indexOf('!');
var jar = fileUrl.substring(colon + 1, exclamation);
var internalFile = fileUrl.substring(exclamation + 2);
try (var jarFile = new JarFile(jar)) {
Enumeration<JarEntry> entries = jarFile.entries();
while (entries.hasMoreElements()) {
var jarEntry = entries.nextElement();
String name = jarEntry.getName();
if (name.startsWith(internalFile) && name.toLowerCase().endsWith(".md")) {
pages.add(name.substring(name.lastIndexOf('/') + 1));
}
}
}
}
private void indexDirectory(URL resource, List<String> pages) {
var docs = new File(resource.getFile());
String[] files = docs.list((dir, name) -> name.toLowerCase().endsWith(".md"));
pages.addAll(Arrays.asList(files));
}
String loadMarkdown(String path) throws IOException {
var contextPath = getServletContext().getContextPath();
if (contextPath != null && path.startsWith(contextPath)) {
path = path.substring(contextPath.length());
}
return loadFile(path);
}
protected void error(HttpServletResponse resp, int status, String message) {
try {
resp.setStatus(status);
resp.getWriter().println(getHeader());
String html = loadFile(CLASSPATH_DIR + "/" + status + ".html");
if (message == null || message.trim().isEmpty()) {
message = "";
}
html = html.replace("{message}", message);
html = renderContextAwareUris(html);
resp.getWriter().println(html);
resp.getWriter().println(getFooter());
} catch (IOException e) {
log.error("Error while sending error response. Man, his is bad!", e);
}
}
}