Merge pull request #30 from elisherer/feature/retry_with_https

mimic follow redirects of http to https in case content received empty

library/src/main/java/net/jimblackler/jsonschemafriend/CacheLoader.java

@@ -1,9 +1,6 @@
 package net.jimblackler.jsonschemafriend;
 
-import static net.jimblackler.jsonschemafriend.StreamUtils.streamToString;
-
 import java.io.IOException;
-import java.io.InputStream;
 import java.io.PrintWriter;
 import java.net.URI;
 import java.nio.file.FileSystem;
@@ -24,18 +21,17 @@ public String load(URI uri, boolean cacheSchema) throws IOException {
                                .resolve(uri.getHost() + uri.getPath());
       if (Files.exists(diskCacheName)) {
         LOG.fine("Cache loading: " + uri + System.lineSeparator() + "From: " + diskCacheName);
-        return streamToString(diskCacheName.toUri().toURL().openStream());
+        return UrlUtils.readFromStream(diskCacheName.toUri().toURL());
       }
-      String content = streamToString(uri.toURL().openStream());
+      String content = UrlUtils.readFromStream(uri.toURL());
       diskCacheName.getParent().toFile().mkdirs();
       try (PrintWriter out = new PrintWriter(diskCacheName.toFile())) {
         out.println(content);
       }
       return content;
     }
     LOG.fine("Loading :" + uri);
-    try (InputStream stream = uri.toURL().openStream()) {
-      return streamToString(stream);
-    }
+
+    return UrlUtils.readFromStream(uri.toURL());
   }
 }

library/src/main/java/net/jimblackler/jsonschemafriend/UrlUtils.java

@@ -0,0 +1,24 @@
+package net.jimblackler.jsonschemafriend;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+
+import static net.jimblackler.jsonschemafriend.StreamUtils.streamToString;
+
+public class UrlUtils {
+  static String readFromStream(URL url) throws IOException {
+    String result;
+    try (InputStream stream = url.openStream()) {
+      result = streamToString(stream);
+    }
+    if (result.isEmpty() && "http".equals(url.getProtocol())) {
+      // in case tried http and received empty content, try to connect to same url with https
+      URL secureUrl = new URL(url.toString().replaceFirst("http", "https"));
+      try (InputStream stream = secureUrl.openStream()) {
+        result = streamToString(stream);
+      }
+    }
+    return result;
+  }
+}

library/src/main/java/net/jimblackler/jsonschemafriend/Validator.java

@@ -731,7 +731,7 @@ public void validate(Schema schema, InputStream inputStream)
 
   public void validate(Schema schema, URL url, Consumer<ValidationError> errorConsumer)
       throws IOException {
-    validate(schema, new ObjectMapper().readValue(url.openStream(), Object.class), errorConsumer);
+    validate(schema, new ObjectMapper().readValue(UrlUtils.readFromStream(url), Object.class), errorConsumer);
   }
 
   public void validate(Schema schema, URI uri, Consumer<ValidationError> errorConsumer)