Transaction Support (#67)

* Add startTransaction for creating transactions

* Add transaction header constants

* Add method to retrieve transaction uri

* Add method to add Atomic-Id header for transactions

* Use transaction endpoint constant

* Override addTransaction for all builders

* Initial TransactionBuilder idea

* Checkstyle updates

* Create RequestBuilders per transaction endpoint

* Move start and TRANSACTION_ENDPOINT to TransactionBuilder

* Add uri validation methods

* Add simple tests for tx uri validation

* Split start valid into separate tests

* Use regex from fcrepo for validation help on tx ids

* Create TransactionURI for more strict api definitions

* Update ATOMIC_ID constant

* Try to retrieve the Atomic-ID from a response when getting the transaction uri

* Add TransactionalFcrepoClient for automatically adding Atomic-IDs to requests

* Add builder option for a TransactionFcrepoClient

* Create a container to test the transactional client

* Use DateTimeFormatter when checking all Atomic-Expires headers

* Add a method for creating transaction clients from a fcrepo client

Updates the FcrepoClient constructor to take a HttpClientBuilder in order to construct new clients

* Extend BodyRequestBuilder to allow for removal of addTransaction

* Make addTransaction protected to hide it in unused builders

* Add function to start a tx and create a client

* Test for startTransactionalClient

* Drop Optional from getTransactionUri

* Add transaction helpers to client

* Move startTransactionClient to FcrepoClient

* Update tests to be only through TransactionalFcrepoClient

* Create RequestBuilders for tx endpoints in TransactionalFcrepoClient

* Update import for TRANSACTION_ENDPOINT

* Remove unused classes

* Shorten transaction methods

* Keep functionality for base or transaction endpoints

* Add test creating a client using the full transaction endpoint

* Drop need for TransactionURI

* Use Get/Post/etc builders for the transaction api

src/main/java/org/fcrepo/client/DeleteBuilder.java

@@ -35,4 +35,10 @@ protected HttpRequestBase createRequest() {
     public DeleteBuilder addHeader(final String name, final String value) {
         return (DeleteBuilder) super.addHeader(name, value);
     }
+
+    @Override
+    public DeleteBuilder addTransaction(final URI transaction) {
+        return (DeleteBuilder) super.addTransaction(transaction);
+    }
+
 }

src/main/java/org/fcrepo/client/FcrepoClient.java

@@ -16,6 +16,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
+import java.util.regex.Pattern;
 
 import org.apache.http.Header;
 import org.apache.http.HttpEntity;
@@ -48,9 +49,12 @@
 public class FcrepoClient implements Closeable {
 
     private CloseableHttpClient httpclient;
+    private FcrepoHttpClientBuilder httpClientBuilder;
 
     private Boolean throwExceptionOnFailure = true;
 
+    public static final String TRANSACTION_ENDPOINT = "fcr:tx";
+
     private static final Logger LOGGER = getLogger(FcrepoClient.class);
 
     /**
@@ -72,7 +76,19 @@ public static FcrepoClientBuilder client() {
      */
     protected FcrepoClient(final String username, final String password, final String host,
             final Boolean throwExceptionOnFailure) {
-        this(new FcrepoHttpClientBuilder(username, password, host).build(), throwExceptionOnFailure);
+        this(new FcrepoHttpClientBuilder(username, password, host), throwExceptionOnFailure);
+    }
+
+    /**
+     * Create a FcrepoClient which uses the given {@link FcrepoHttpClientBuilder} to manage its http client.
+     * FcrepoClient will close the httpClient when {@link #close()} is called.
+     * @param httpClientBuilder http client builder to use to connect to the repository
+     * @param throwExceptionOnFailure whether to throw an exception on any non-2xx or 3xx HTTP responses
+     */
+    protected FcrepoClient(final FcrepoHttpClientBuilder httpClientBuilder, final Boolean throwExceptionOnFailure) {
+        this.throwExceptionOnFailure = throwExceptionOnFailure;
+        this.httpclient = httpClientBuilder.build();
+        this.httpClientBuilder = httpClientBuilder;
     }
 
     /**
@@ -152,6 +168,49 @@ public HistoricMementoBuilder createMemento(final URI url, final String mementoD
         return new HistoricMementoBuilder(url, this, mementoDatetime);
     }
 
+    /**
+     * Start a transaction and create a new {@link TransactionalFcrepoClient}
+     *
+     * @param uri the base rest endpoint or the transaction endpoint
+     * @return the TransactionalFcrepoClient
+     * @throws IOException if there's an error with the http request
+     * @throws IllegalArgumentException if the uri is not the Fedora transaction endpoint
+     * @throws FcrepoOperationFailedException if there's an error in the fcrepo operation
+     */
+    public TransactionalFcrepoClient startTransactionClient(final URI uri)
+        throws IOException, FcrepoOperationFailedException {
+        final var target = getTxEndpoint(uri);
+        try (final var response = post(target).perform()) {
+            return transactionalClient(response);
+        }
+    }
+
+    private URI getTxEndpoint(final URI uri) {
+        final var isRoot = Pattern.compile("rest/?$").asPredicate();
+        final var isTx = Pattern.compile("rest/" + TRANSACTION_ENDPOINT + "/?$").asPredicate();
+        final var base = uri.toString();
+        if (isRoot.test(base)) {
+            LOGGER.debug("Start transaction request matches root, appending {}", TRANSACTION_ENDPOINT);
+            // preface with ./ so fcr:tx isn't interpreted as a scheme
+            return uri.resolve("./" + TRANSACTION_ENDPOINT);
+        } else if (isTx.test(base)) {
+            return uri;
+        } else {
+            throw new IllegalArgumentException("Uri is not the base rest endpoint or the transaction endpoint");
+        }
+    }
+
+    /**
+     * Create a new {@link TransactionalFcrepoClient} which adds the transaction {@link URI} to each request
+     *
+     * @param response the FcrepoResponse with an Atomic-ID Header
+     * @return a TransactionFcrepoClient
+     * @throws IllegalArgumentException if the FcrepoResponse does not contain a transaction location
+     */
+    public TransactionalFcrepoClient transactionalClient(final FcrepoResponse response) {
+        return new TransactionalFcrepoClient(response.getTransactionUri(), httpClientBuilder, throwExceptionOnFailure);
+    }
+
     /**
      * Make a DELETE request to delete a resource
      *
@@ -354,7 +413,7 @@ public FcrepoClientBuilder throwExceptionOnFailure() {
          */
         public FcrepoClient build() {
             final FcrepoHttpClientBuilder httpClient = new FcrepoHttpClientBuilder(authUser, authPassword, authHost);
-            return new FcrepoClient(httpClient.build(), throwExceptionOnFailure);
+            return new FcrepoClient(httpClient, throwExceptionOnFailure);
         }
     }
 }

src/main/java/org/fcrepo/client/FcrepoResponse.java

@@ -7,6 +7,8 @@
 
 import static java.util.Collections.emptyList;
 import static java.util.stream.Collectors.toList;
+import static org.fcrepo.client.FcrepoClient.TRANSACTION_ENDPOINT;
+import static org.fcrepo.client.FedoraHeaderConstants.ATOMIC_ID;
 import static org.fcrepo.client.FedoraHeaderConstants.CONTENT_DISPOSITION;
 import static org.fcrepo.client.FedoraHeaderConstants.CONTENT_TYPE;
 import static org.fcrepo.client.FedoraHeaderConstants.LINK;
@@ -20,6 +22,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+
 import org.apache.http.HeaderElement;
 import org.apache.http.NameValuePair;
 import org.apache.http.message.BasicHeader;
@@ -56,6 +59,8 @@ public class FcrepoResponse implements Closeable {
 
     private InputStream body;
 
+    private URI transactionUri;
+
     private String contentType;
 
     private boolean closed = false;
@@ -313,4 +318,26 @@ public Map<String, String> getContentDisposition() {
         }
         return contentDisposition;
     }
+
+    /**
+     * Get the transaction location. If the location is not for a transaction, check for the Atomic-ID,
+     * otherwise return null.
+     *
+     * @return the transaction location or null
+     */
+    public URI getTransactionUri() {
+        if (transactionUri == null) {
+            final var location = getHeaderValue(LOCATION);
+            final var atomicId = getHeaderValue(ATOMIC_ID);
+
+            if (location != null && location.contains(TRANSACTION_ENDPOINT)) {
+                transactionUri = URI.create(location);
+            } else if (atomicId != null) {
+                transactionUri = URI.create(atomicId);
+            }
+        }
+
+        return transactionUri;
+    }
+
 }

src/main/java/org/fcrepo/client/FedoraHeaderConstants.java

@@ -67,6 +67,10 @@ public class FedoraHeaderConstants {
 
     public static final String ACCEPT_DATETIME = "Accept-Datetime";
 
+    public static final String ATOMIC_ID = "Atomic-ID";
+
+    public static final String ATOMIC_EXPIRES = "Atomic-Expires";
+
     private FedoraHeaderConstants() {
     }
 }

src/main/java/org/fcrepo/client/GetBuilder.java

@@ -182,4 +182,9 @@ public GetBuilder addHeader(final String name, final String value) {
     public GetBuilder addLinkHeader(final FcrepoLink linkHeader) {
         return (GetBuilder) super.addLinkHeader(linkHeader);
     }
+
+    @Override
+    public GetBuilder addTransaction(final URI transaction) {
+        return (GetBuilder) super.addTransaction(transaction);
+    }
 }

src/main/java/org/fcrepo/client/HeadBuilder.java

@@ -67,4 +67,9 @@ public HeadBuilder addHeader(final String name, final String value) {
     public HeadBuilder addLinkHeader(final FcrepoLink linkHeader) {
         return (HeadBuilder) super.addLinkHeader(linkHeader);
     }
+
+    @Override
+    public HeadBuilder addTransaction(final URI transaction) {
+        return (HeadBuilder) super.addTransaction(transaction);
+    }
 }

src/main/java/org/fcrepo/client/HistoricMementoBuilder.java

@@ -5,19 +5,27 @@
  */
 package org.fcrepo.client;
 
+import static org.fcrepo.client.FedoraHeaderConstants.CONTENT_DISPOSITION;
+import static org.fcrepo.client.FedoraHeaderConstants.SLUG;
 import static org.fcrepo.client.HeaderHelpers.UTC_RFC_1123_FORMATTER;
 import static org.fcrepo.client.FedoraHeaderConstants.MEMENTO_DATETIME;
 
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
 import java.net.URI;
 import java.time.Instant;
 
+import org.apache.http.client.methods.HttpRequestBase;
+import org.springframework.http.ContentDisposition;
+
 /**
  * Builds a POST request for creating a memento (LDPRm) with the state given in the request body
  * and the datetime given in the Memento-Datetime request header.
  *
  * @author bbpennel
  */
-public class HistoricMementoBuilder extends PostBuilder {
+public class HistoricMementoBuilder extends BodyRequestBuilder {
 
     /**
      * Instantiate builder
@@ -45,4 +53,101 @@ public HistoricMementoBuilder(final URI uri, final FcrepoClient client, final St
         UTC_RFC_1123_FORMATTER.parse(mementoDatetime);
         request.setHeader(MEMENTO_DATETIME, mementoDatetime);
     }
+
+    @Override
+    protected HttpRequestBase createRequest() {
+        return HttpMethods.POST.createRequest(targetUri);
+    }
+
+    @Override
+    public HistoricMementoBuilder body(final InputStream stream, final String contentType) {
+        return (HistoricMementoBuilder) super.body(stream, contentType);
+    }
+
+    @Override
+    public HistoricMementoBuilder body(final File file, final String contentType) throws IOException {
+        return (HistoricMementoBuilder) super.body(file, contentType);
+    }
+
+    @Override
+    public HistoricMementoBuilder body(final InputStream stream) {
+        return (HistoricMementoBuilder) super.body(stream);
+    }
+
+    @Override
+    public HistoricMementoBuilder externalContent(final URI contentURI,
+                                                  final String contentType,
+                                                  final String handling) {
+        return (HistoricMementoBuilder) super.externalContent(contentURI, contentType, handling);
+    }
+
+    @Override
+    public HistoricMementoBuilder digest(final String digest, final String alg) {
+        return (HistoricMementoBuilder) super.digest(digest, alg);
+    }
+
+    @Override
+    public HistoricMementoBuilder digestMd5(final String digest) {
+        return (HistoricMementoBuilder) super.digestMd5(digest);
+    }
+
+    @Override
+    public HistoricMementoBuilder digestSha1(final String digest) {
+        return (HistoricMementoBuilder) super.digestSha1(digest);
+    }
+
+    @Override
+    public HistoricMementoBuilder digestSha256(final String digest) {
+        return (HistoricMementoBuilder) super.digestSha256(digest);
+    }
+
+    @Override
+    public HistoricMementoBuilder addInteractionModel(final String interactionModelUri) {
+        return (HistoricMementoBuilder) super.addInteractionModel(interactionModelUri);
+    }
+
+    @Override
+    public HistoricMementoBuilder linkAcl(final String aclUri) {
+        return (HistoricMementoBuilder) super.linkAcl(aclUri);
+    }
+
+    @Override
+    public HistoricMementoBuilder addHeader(final String name, final String value) {
+        return (HistoricMementoBuilder) super.addHeader(name, value);
+    }
+
+    @Override
+    public HistoricMementoBuilder addLinkHeader(final FcrepoLink linkHeader) {
+        return (HistoricMementoBuilder) super.addLinkHeader(linkHeader);
+    }
+
+    /**
+     * Provide a content disposition header which will be used as the filename
+     *
+     * @param filename the name of the file being provided in the body of the request
+     * @return this builder
+     * @throws FcrepoOperationFailedException if unable to encode filename
+     */
+    public HistoricMementoBuilder filename(final String filename) throws FcrepoOperationFailedException {
+        final ContentDisposition.Builder builder = ContentDisposition.builder("attachment");
+        if (filename != null) {
+            builder.filename(filename);
+        }
+        request.addHeader(CONTENT_DISPOSITION, builder.build().toString());
+        return this;
+    }
+
+    /**
+     * Provide a suggested name for the new child resource, which the repository may ignore.
+     *
+     * @param slug value to supply as the slug header
+     * @return this builder
+     */
+    public HistoricMementoBuilder slug(final String slug) {
+        if (slug != null) {
+            request.addHeader(SLUG, slug);
+        }
+        return this;
+    }
+
 }

src/main/java/org/fcrepo/client/OptionsBuilder.java

@@ -40,4 +40,9 @@ public OptionsBuilder addHeader(final String name, final String value) {
     public OptionsBuilder addLinkHeader(final FcrepoLink linkHeader) {
         return (OptionsBuilder) super.addLinkHeader(linkHeader);
     }
+
+    @Override
+    public OptionsBuilder addTransaction(final URI transaction) {
+        return (OptionsBuilder) super.addTransaction(transaction);
+    }
 }

src/main/java/org/fcrepo/client/OriginalMementoBuilder.java

@@ -40,4 +40,5 @@ public OriginalMementoBuilder addHeader(final String name, final String value) {
     public OriginalMementoBuilder addLinkHeader(final FcrepoLink linkHeader) {
         return (OriginalMementoBuilder) super.addLinkHeader(linkHeader);
     }
+
 }

src/main/java/org/fcrepo/client/PatchBuilder.java

@@ -101,4 +101,9 @@ public PatchBuilder addHeader(final String name, final String value) {
     public PatchBuilder addLinkHeader(final FcrepoLink linkHeader) {
         return (PatchBuilder) super.addLinkHeader(linkHeader);
     }
+
+    @Override
+    public PatchBuilder addTransaction(final URI transaction) {
+        return (PatchBuilder) super.addTransaction(transaction);
+    }
 }

src/main/java/org/fcrepo/client/PostBuilder.java

@@ -101,6 +101,11 @@ public PostBuilder addHeader(final String name, final String value) {
         return (PostBuilder) super.addHeader(name, value);
     }
 
+    @Override
+    public PostBuilder addTransaction(final URI transaction) {
+        return (PostBuilder) super.addTransaction(transaction);
+    }
+
     @Override
     public PostBuilder addLinkHeader(final FcrepoLink linkHeader) {
         return (PostBuilder) super.addLinkHeader(linkHeader);

src/main/java/org/fcrepo/client/PutBuilder.java

@@ -121,6 +121,11 @@ public PutBuilder addLinkHeader(final FcrepoLink linkHeader) {
         return (PutBuilder) super.addLinkHeader(linkHeader);
     }
 
+    @Override
+    public PutBuilder addTransaction(final URI transaction) {
+        return (PutBuilder) super.addTransaction(transaction);
+    }
+
     /**
      * Provide a content disposition header which will be used as the filename
      *