HttpEncoder StreamUtils Preconditions

maxkey-common/src/main/java/org/maxkey/util/StreamUtils.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright [2022] [MaxKey of copyright http://www.maxkey.top]
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+ 
+package org.maxkey.util;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.util.zip.GZIPInputStream;
+
+/**
+ * Utils to deal with Streams.
+ */
+public abstract class StreamUtils {
+
+    /**
+     * Returns the stream contents as an UTF-8 encoded string
+     *
+     * @param is input stream
+     * @return string contents
+     * @throws java.io.IOException in any. SocketTimeout in example
+     */
+    public static String getStreamContents(InputStream is) throws IOException {
+        Preconditions.checkNotNull(is, "Cannot get String from a null object");
+        final char[] buffer = new char[0x10000];
+        final StringBuilder out = new StringBuilder();
+        try (Reader in = new InputStreamReader(is, "UTF-8")) {
+            int read;
+            do {
+                read = in.read(buffer, 0, buffer.length);
+                if (read > 0) {
+                    out.append(buffer, 0, read);
+                }
+            } while (read >= 0);
+        }
+        return out.toString();
+    }
+
+    /**
+     * Return String content from a gzip stream
+     *
+     * @param is input stream
+     * @return string contents
+     * @throws java.io.IOException in any. SocketTimeout in example
+     */
+    public static String getGzipStreamContents(InputStream is) throws IOException {
+        Preconditions.checkNotNull(is, "Cannot get String from a null object");
+        final GZIPInputStream gis = new GZIPInputStream(is);
+        return getStreamContents(gis);
+    }
+}