Attachment: add support for authenticated downloads of attachments (#12)

README.md

@@ -19,3 +19,11 @@ This wraps the `com.taskadapter:trello-java-wrapper` library.
 It is intended for use on my `slushy` and `fuller` projects. It was originally developed as part of `slushy` and was extracted when preparing to start on `fuller` which would need some of the same functionality.
 
 Requires JDK 11+
+
+## Downloading Attachments
+
+From 1.1.0 of `kemitix-trello` support is included for downloading attachments
+using the now required authorised methods. In order to do so the API key and 
+token are needed to download the attachment. These are provided either when 
+creating the new `TrelloAttachment` constructor, or by calling the method
+`withApiKeyPair(...)`, which will return a new instance.

pom.xml

@@ -12,7 +12,7 @@
     </parent>
 
     <artifactId>kemitix-trello</artifactId>
-    <version>1.0.3</version>
+    <version>1.1.0</version>
 
     <properties>
         <tiles-maven-plugin.version>2.18</tiles-maven-plugin.version>

src/main/java/net/kemitix/trello/ApiKeyPair.java

@@ -0,0 +1,16 @@
+package net.kemitix.trello;
+
+public interface ApiKeyPair {
+
+    String getKey();
+    String getToken();
+
+    static ApiKeyPair create(String key, String token) {
+        return new ApiKeyPairImpl(key, token);
+    }
+
+    static ApiKeyPair none() {
+        return ApiKeyPairImpl.NONE;
+    }
+
+}

src/main/java/net/kemitix/trello/ApiKeyPairImpl.java

@@ -0,0 +1,16 @@
+package net.kemitix.trello;
+
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor(access = AccessLevel.PROTECTED)
+public class ApiKeyPairImpl implements ApiKeyPair {
+
+    public static final ApiKeyPair NONE = new ApiKeyPairImpl("", "");
+
+    private final String key;
+    private final String token;
+
+}

src/main/java/net/kemitix/trello/Attachment.java

@@ -25,4 +25,13 @@ public interface Attachment {
      */
     File getOriginalFilename();
 
+    /**
+     * Adds the API Key Pair to a {@link TrelloAttachment}, creating a new
+     * instance, but ignored otherwise.
+     *
+     * @param apiKeyPair the key pair to add
+     * @return a new TrelloAttachment instance or itself
+     */
+    Attachment withApiKeyPair(final ApiKeyPair apiKeyPair);
+
 }

src/main/java/net/kemitix/trello/LocalAttachment.java

@@ -35,4 +35,9 @@ public class LocalAttachment
     public LocalAttachment download() {
         return this;
     }
+
+    @Override
+    public Attachment withApiKeyPair(ApiKeyPair apiKeyPair) {
+        return this;
+    }
 }

src/main/java/net/kemitix/trello/TrelloAttachment.java

@@ -5,12 +5,13 @@ import com.julienvey.trello.domain.Card;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.net.Authenticator;
+import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
 import java.net.URI;
 import java.net.URL;
-import java.net.URLEncoder;
+import java.net.URLConnection;
 import java.nio.channels.Channels;
-import java.nio.charset.StandardCharsets;
 import java.text.Normalizer;
 import java.util.Optional;
 import java.util.logging.Logger;
@@ -25,16 +26,19 @@ public class TrelloAttachment implements Attachment {
     private final Card card;
     private final AttachmentDirectory attachmentDirectory;
     private final String id;
+    private final ApiKeyPair apiKeyPair;
 
     private TrelloAttachment(
             com.julienvey.trello.domain.Attachment attachment,
             Card card,
-            AttachmentDirectory attachmentDirectory
+            AttachmentDirectory attachmentDirectory,
+            ApiKeyPair apiKeyPair
     ) {
         this.attachment = attachment;
         this.card = card;
         this.attachmentDirectory = attachmentDirectory;
         this.id = card.getIdShort();
+        this.apiKeyPair = apiKeyPair;
     }
 
     public static Attachment create(
@@ -42,7 +46,16 @@ public class TrelloAttachment implements Attachment {
             Card card,
             AttachmentDirectory dir
     ) {
-        return new TrelloAttachment(attachment, card, dir);
+        return new TrelloAttachment(attachment, card, dir, ApiKeyPair.none());
+    }
+
+    public static Attachment create(
+            com.julienvey.trello.domain.Attachment attachment,
+            Card card,
+            AttachmentDirectory dir,
+            ApiKeyPair apiKeyPair
+    ) {
+        return new TrelloAttachment(attachment, card, dir, apiKeyPair);
     }
 
     @Override
@@ -67,7 +80,11 @@ public class TrelloAttachment implements Attachment {
 
     @Override
     public LocalAttachment download() {
-        try (var source = Channels.newChannel(getUrl().openStream());){
+        if (apiKeyPair == ApiKeyPair.none()) {
+            throw new UnsupportedOperationException(
+                    "Download not permitted without a valid API KeyPair");
+        }
+        try (var source = Channels.newChannel(getConnection().getInputStream());) {
             File filename = new File(attachment.getName());
             LOG.info("Downloading from " + filename);
             var file = attachmentDirectory.createFile(getFilename());
@@ -82,11 +99,24 @@ public class TrelloAttachment implements Attachment {
         }
     }
 
+    private URLConnection getConnection() throws IOException {
+        var connection = (HttpURLConnection) getUrl().openConnection();
+        connection.setRequestProperty("Authorization", String.format(
+                "OAuth oauth_consumer_key=\"%s\", oauth_token=\"%s\"",
+                apiKeyPair.getKey(), apiKeyPair.getToken()));
+        return connection;
+    }
+
     @Override
     public File getOriginalFilename() {
         return getFilename();
     }
 
+    @Override
+    public Attachment withApiKeyPair(ApiKeyPair apiKeyPair) {
+        return create(attachment, card, attachmentDirectory, apiKeyPair);
+    }
+
     private URL getUrl() throws MalformedURLException {
         return URI.create(attachment.getUrl()).toURL();
     }