Step 5: Add receipt.png

You can use the Java Client Libraries to save non-RDF resources (e.g., .png, .pdf) to your Pod.

For this part of the tutorial, the getting started app uses Inrupt’s Java client library to:

• Store a copy of the expense receipt(s) to your Pod.

• Update the associated expense to link to the URL(s) of the receipt(s).

Tip

You can find the complete code at Complete Code.

Update application.properties

Add the following properties to the src/main/resources/application.properties file:

spring.servlet.multipart.max-file-size=128KB
spring.servlet.multipart.max-request-size=128KB

Modify Expense Class

1. Open Expense class file:

   JavaKotlin

   Open src/main/java/com/example/gettingstarted/Expense.java.

2. Add the java.util.* import statement:

   JavaKotlin

   import java.util.*;
   

3. Add the predicate definition for the receipts in the Expense class:

   JavaKotlin

   static IRI SCHEMA_IMAGE = rdf.createIRI("https://schema.org/image");
   

4. Update the Expense class constructor to include the receipts:

   JavaKotlin

   @JsonCreator
   public Expense(@JsonProperty("identifier") final URI identifier,
                  @JsonProperty("merchantProvider") String merchantProvider,
                  @JsonProperty("expenseDate") Date expenseDate,
                  @JsonProperty("description") String description,
                  @JsonProperty("amount") BigDecimal amount,
                  @JsonProperty("currency") String currency,
                  @JsonProperty("category") String category,
                  @JsonProperty("receipts") String[] receipts) {
       this(identifier);
       this.setRdfType(MY_RDF_TYPE_VALUE);
       this.setMerchantProvider(merchantProvider);
       this.setExpenseDate(expenseDate);
       this.setDescription(description);
       this.setAmount(amount);
       this.setCurrency(currency);
       this.setCategory(category);
       this.setReceipts(receipts);
   }
   

5. Add the getter and setters for the receipts in the Expense class:

   JavaKotlin

   public Set<String> getReceipts() {
       return subject.getReceipts();
   }
   // Note:: The setters first uses the getter, which returns a Set, and adds the receipt to the set.
   public void addReceipt(String receipt) {
       subject.getReceipts().add(receipt);
   }
   public void setReceipts(String[] receipts) {
       subject.getReceipts().addAll(List.of(receipts));
   }
   

6. Add getter for the receipts in the inner Node class:

   JavaKotlin

   public Set<String> getReceipts() {
       return objects(SCHEMA_IMAGE, TermMappings::asIri, ValueMappings::iriAsString);
   }
   

Note

For more detail with regards to handling lists, see Data Modeling (RDF).

Modify ExpenseController Class

1. Open ExpenseController class file.

   JavaKotlin

   Open src/main/java/com/example/gettingstarted/ExpenseController.java.

2. Add the following import statement:

   JavaKotlin

   import org.springframework.web.multipart.MultipartFile;
   

3. Add the following method to handle the upload of non-RDF files:

   JavaKotlin

   /**
    * Note 9: Stores a non-RDF resource to a Pod
    *
    * - Build a PUT request using Request.newBuilder()...build();
    * - Send the request using SolidSyncClient's low-level client.send() method;
    */
   @PutMapping("/resource/nonRDF/add")
   public boolean addNonRDFFile(@RequestParam(value = "destinationURL") String destinationURL,
                                @RequestParam(value = "file") MultipartFile file) {
       printWriter.println("In addNonRDFFile:: Save Non-RDF File to Pod.");
       try (final var fileStream = file.getInputStream()) {
           Request request = Request.newBuilder()
                   .uri(URI.create(destinationURL))
                   .header("Content-Type", file.getContentType())
                   .PUT(Request.BodyPublishers.ofInputStream(fileStream))
                   .build();
           Response<Void> response = client.send(
                   request,
                   Response.BodyHandlers.discarding());
           if (response.statusCode() == 201 || response.statusCode() == 200 || response.statusCode() == 204)
               return true;
       } catch (java.io.IOException e1) {
           e1.printStackTrace();
       }
   
       return false;
   }
   

4. Add the following method that uploads a receipt file and links it to the associated Expense.

   JavaKotlin

   /**
    * Note 10: Stores a non-RDF resource (image of the receipt) to a Pod and Attach to an Expense
    * Using methods defined as part of getting started, addReceiptToExpense:
    * - Calls addNonRDFFile() to store the receipt to a Pod
    * - Calls getExpense() to fetch the associated Expense RDF resource.
    * - Calls the Expense's setter `addReceipt` to add the link to the saved receipt.
    * - Calls updateExpense() to save the updated Expense.
    */
   @PutMapping("/expenses/receipts/add")
   public String addReceiptToExpense(@RequestParam(value = "destinationURL") String destinationURL,
                                     @RequestParam(value = "file") MultipartFile file,
                                     @RequestParam(value = "expenseURL") String expenseURL) {
       printWriter.println("In addReceiptToExpense: Save Receipt File to Pod and Update Associated Expense.");
       boolean success = addNonRDFFile(destinationURL, file);
       if (success) {
           Expense expense = getExpense(expenseURL);
           expense.addReceipt(destinationURL);
           return updateExpense(expense);
       } else {
           printWriter.println("Error adding receipt");
           return null;
       }
   }