https://github.com/itplr-kosit/validator/issues/57 fix read stream

pom.xml

@@ -507,7 +507,7 @@
             <plugin>
                 <groupId>net.revelc.code.formatter</groupId>
                 <artifactId>formatter-maven-plugin</artifactId>
-                <version>2.12.2</version>
+                <version>2.13.0</version>
                 <executions>
                     <execution>
                         <id>validate</id>
@@ -519,6 +519,7 @@
                 </executions>
                 <configuration>
                     <configFile>${project.basedir}/formatter.xml</configFile>
+                    <lineEnding>LF</lineEnding>
                 </configuration>
             </plugin>
         </plugins>

src/main/java/de/kosit/validationtool/daemon/CheckHandler.java

@@ -1,11 +1,13 @@
 package de.kosit.validationtool.daemon;
 
+import java.io.BufferedInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.InputStream;
 import java.net.URI;
 import java.util.concurrent.atomic.AtomicLong;
 
+import org.apache.commons.lang3.StringUtils;
+
 import com.sun.net.httpserver.HttpExchange;
 
 import lombok.RequiredArgsConstructor;
@@ -15,6 +17,7 @@ import de.kosit.validationtool.api.Check;
 import de.kosit.validationtool.api.InputFactory;
 import de.kosit.validationtool.api.Result;
 import de.kosit.validationtool.impl.input.SourceInput;
+import de.kosit.validationtool.impl.input.StreamHelper;
 
 import net.sf.saxon.s9api.Processor;
 import net.sf.saxon.s9api.SaxonApiException;
@@ -47,9 +50,9 @@ class CheckHandler extends BaseHandler {
             final String requestMethod = httpExchange.getRequestMethod();
             // check neccessary, since gui can be disabled
             if (requestMethod.equals("POST")) {
-                final InputStream inputStream = httpExchange.getRequestBody();
+                final BufferedInputStream buffered = StreamHelper.wrapPeekable(httpExchange.getRequestBody());
-                if (inputStream.available() > 0) {
+                if (!isMultipartFormData(httpExchange) && isContentAvailable(httpExchange, buffered)) {
-                    final SourceInput serverInput = (SourceInput) InputFactory.read(inputStream,
+                    final SourceInput serverInput = (SourceInput) InputFactory.read(buffered,
                             resolveInputName(httpExchange.getRequestURI()));
                     final Result result = this.implemenation.checkInput(serverInput);
                     write(httpExchange, serialize(result), APPLICATION_XML, resolveStatus(result));
@@ -61,10 +64,29 @@ class CheckHandler extends BaseHandler {
                 error(httpExchange, HttpStatus.SC_METHOD_NOT_ALLOWED, "Method not supported");
             }
         } catch (final Exception e) {
+            log.error("Error checking entity", e);
             error(httpExchange, HttpStatus.SC_INTERNAL_SERVER_ERROR, "Internal error: " + e.getMessage());
         }
     }
 
+    private static boolean isContentAvailable(final com.sun.net.httpserver.HttpExchange httpExchange, final BufferedInputStream buffered)
+            throws IOException {
+        final String length = httpExchange.getRequestHeaders().getFirst("Content-length");
+        if (StringUtils.isNumeric(length)) {
+            return Integer.parseInt(length) > 0;
+        }
+        return streamContainsContent(buffered);
+    }
+
+    private static boolean isMultipartFormData(final HttpExchange httpExchange) {
+        return httpExchange.getRequestHeaders().getFirst("Content-type").startsWith("multipart");
+    }
+
+    private static boolean streamContainsContent(final BufferedInputStream requestBody) throws IOException {
+        return requestBody.available() > 0;
+
+    }
+
     private static String resolveInputName(final URI requestURI) {
         final String path = requestURI.getPath();
         if (path.equalsIgnoreCase("/")) {

src/main/java/de/kosit/validationtool/impl/input/StreamHelper.java

@@ -1,5 +1,6 @@
 package de.kosit.validationtool.impl.input;
 
+import java.io.BufferedInputStream;
 import java.io.FilterInputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -45,6 +46,35 @@ public class StreamHelper {
 
     }
 
+    private static class PeekableInputStream extends BufferedInputStream {
+
+        public PeekableInputStream(final InputStream in) {
+            super(in);
+        }
+
+        @Override
+        public synchronized int available() throws IOException {
+            int count = super.available();
+            if (count == 0) {
+                count = peek();
+            }
+            return count;
+        }
+
+        @SuppressWarnings("ResultOfMethodCallIgnored")
+        private int peek() throws IOException {
+            try {
+                mark(2);
+                read();
+                read();
+                reset();
+            } catch (final IOException e) {
+                return 0;
+            }
+            return super.available();
+        }
+    }
+
     @SuppressWarnings("squid:S4929") // efficient read is done by internally used stream
     private static class CountInputStream extends FilterInputStream {
 
@@ -103,6 +133,10 @@ public class StreamHelper {
         return new DigestingInputStream(input, stream, createDigest(digestAlgorithm));
     }
 
+    public static BufferedInputStream wrapPeekable(final InputStream stream) {
+        return new PeekableInputStream(stream);
+    }
+
     /**
      * Drains the {@link Input} without further processing. This is useful to computing hashcode etc.
      * 
@@ -129,8 +163,10 @@ public class StreamHelper {
     public static void drain(final InputStream input) throws IOException {
         final byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
 
+        // noinspection unused
         int n;
 
+        // noinspection StatementWithEmptyBody,UnusedAssignment
         while (EOF != (n = input.read(buffer))) {
             // nothing
         }