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:

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

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

    import java.util.*;

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

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

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

    @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:

    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:

    public Set<String> getReceipts() {
    return objects(SCHEMA_ORG_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.

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

  2. Add the following import statements:

    import com.inrupt.client.solid.SolidNonRDFSource;
import org.springframework.web.multipart.MultipartFile;

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

    /**
 * Note 9: Stores a non-RDF resource to a Pod
 *
 * Using SolidNonRDFSource and the SolidSyncClient .create() method,
 * - Saves a non-RDF resource at the destinationURL.
 */
@PutMapping("/resource/nonRDF/add")
public String 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()) {

        SolidNonRDFSource myNonRDFFile = new SolidNonRDFSource(URI.create(destinationURL), file.getContentType(), fileStream);
        return client.create(myNonRDFFile).getIdentifier().toString();
    } catch(PreconditionFailedException e1) {
        // Errors if the resource already exists
        printWriter.println(String.format("[%s] com.inrupt.client.solid.PreconditionFailedException in addNonRDFFile:: %s", e1.getStatusCode(), e1.getMessage()));
    } catch(ForbiddenException e2) {
        // Errors if user does not have access to create
        printWriter.println(String.format("[%s] com.inrupt.client.solid.ForbiddenException in addNonRDFFile:: %s", e2.getStatusCode(), e2.getMessage()));
    } catch(Exception e) {
        e.printStackTrace();
    }

    return null;
}

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

    /**
 * 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 Expense 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.");
    try {
        String receiptLocation = addNonRDFFile(destinationURL, file);
        if (receiptLocation != null) {
            Expense expense = getExpense(expenseURL);
            expense.addReceipt(receiptLocation);
            return updateExpense(expense);
        } else {
            printWriter.println("Error adding receipt");
            return null;
        }
    } catch(ForbiddenException e2) {
        // Errors if user does not have access to read or update the Expense resource
        printWriter.println(String.format("[%s] com.inrupt.client.solid.ForbiddenException in addReceiptToExpense:: %s", e2.getStatusCode(), e2.getMessage()));
    } catch(Exception e) {
        e.printStackTrace();
    }
    return null;
}