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Using Object APIs With Base64 Encoded Files

Liferay DXP 2024.Q2+/Portal 7.4 GA120+

When creating object entries with attachment fields through APIs, you can generally upload files from your computer or use files uploaded to the Documents and Media application. Both scenarios require multiple steps.

You can either upload the document and provide its ID or external reference code (ERC) when posting the object entry via API, or you can post the object entry via API and attach the file to it later through the UI.

Alternatively, you can post object entries with attachments in one step by making a POST request and including a Base64-encoded file in the request body.

Note

Liferay DXP 2024.Q4+ The Objects framework supports External Reference Codes (ERCs) to give you a way to identify external resources across systems.

In particular, the Objects Framework uses ERCs to link attachments to object entries, enabling consistent references across environments. When object entries are imported, their attachments are recognized automatically if present, or placeholders are created for later resolution. Additionally, for attachments uploaded directly by users and hidden from Documents and Media, the content can be included in exported data in Base64 format to facilitate availability upon import.

Before proceeding, set up a new Liferay DXP/Portal 7.4 instance and prepare the provided tutorial code.

Setting Up a Liferay Instance

Start a new Liferay instance by running

docker run -it -m 8g -p 8080:8080 liferay/portal:7.4.3.120-ga120

Sign in to Liferay at http://localhost:8080. Use the email address test@liferay.com and the password test. When prompted, change the password to learn.

Follow these steps to create a basic object for this tutorial:

  1. Open the Global Menu (Global Menu), go to the Control Panel tab, and click Objects.

  2. Click the Add button (Add Button) and enter these values:

    FieldValue
    LabelAble
    Plural LabelAbles
    NameAble

  3. Select the new Object draft, go to the Fields tab, and add the following fields:

    LabelField NameTypeRequest Files
    usersComputerAttachment1usersComputerAttachment1AttachmentUpload Directly from the User's Computer
    usersComputerAttachment2usersComputerAttachment2AttachmentUpload Directly from the User's Computer (Toggle the Show Files in Documents and Media option)
    docsAndMediaAttachmentdocsAndMediaAttachmentAttachmentUpload or Select from Documents and Media Item Selector

    Alternatively, execute ObjectDefinition_POST_ToInstance.sh to create the object definition. Afterward, you can access the object definition at Global Menu → Control Panel → Objects and continue with the next step.

    ./ObjectDefinition_POST_ToInstance.sh

  4. In the Details tab, select Company as the Scope, Object under Panel Link, and click Publish.

    Important

    For this tutorial, you must use the above values.

Once published, you can access the object via APIs.

Preparing the Sample Code

Run the following commands to download and unzip the provided sample code:

curl https://resources.learn.liferay.com/dxp/latest/en/building-applications/objects/understanding-object-integrations/using-custom-object-apis/liferay-p7x7.zip -O

unzip liferay-p7x7.zip

These scripts include the following APIs:

HTTP MethodHTTP EndpointDescription
GET/Returns a complete list of object entries in a Liferay instance; results can be paginated, filtered, searched, and sorted.
POST/Creates object entries using the details provided in the API call.
PUT/[objectNameId]Replaces the specified Object entry’s details with those provided in the API call
DELETE/[objectNameId]Deletes the specified Object entry and returns a 204 if the operation succeeds

  1. After downloading the sample code, navigate to the curl folder in the liferay-p7x7 project.

    cd liferay-p7x7/curl

Posting an Attachment Uploaded Directly From the User’s Computer

To create an object entry with an attachment using the Upload Directly from the User's Computer Request Files option,

  1. Execute Able_POST_FromUsersComputer1.sh. This creates an object entry with a Base64 file attached to it.

    ./Able_POST_FromUsersComputer1.sh

    Use the fileBase64 parameter to attach the file to the object entry.

    ...
	--data-raw '{
		"externalReferenceCode": "ATTACHMENT_FROM_USERS_COMPUTER_1",
		"usersComputerAttachment1": {
			"fileBase64": "iVB0...gg==",
			"name": "AttachmentFromUsersComputer1.png"
		}
...

    The terminal shows a similar output.

    {
   "actions": {
      "permissions": {
         "method": "GET",
         "href": "http://localhost:8080/o/c/ables/32268/permissions"
      },
      "get": {
         "method": "GET",
         "href": "http://localhost:8080/o/c/ables/32268"
      },
      "replace": {
         "method": "PUT",
         "href": "http://localhost:8080/o/c/ables/32268"
      },
      "update": {
         "method": "PATCH",
         "href": "http://localhost:8080/o/c/ables/32268"
      },
      "delete": {
         "method": "DELETE",
         "href": "http://localhost:8080/o/c/ables/32268"
      }
   },
   "creator": {
      "additionalName": "",
      "contentType": "UserAccount",
      "familyName": "Test",
      "givenName": "Test",
      "id": 20122,
      "name": "Test Test"
   },
   "dateCreated": "2024-06-05T16:37:26Z",
   "dateModified": "2024-06-05T16:37:26Z",
   "externalReferenceCode": "ATTACHMENT_FROM_USERS_COMPUTER_1",
   "id": 32268,
   "keywords": [],
   "status": {
      "code": 0,
      "label": "approved",
      "label_i18n": "Approved"
   },
   "taxonomyCategoryBriefs": [],
   "usersComputerAttachment1": {
      "id": 32263,
      "link": {
         "href": "/documents/32260/32262/AttachmentFromUsersComputer1.png/f0a02e6a-8eeb-d021-bfdd-82da1afab1cf?version=1.0&t=1717605446526&download=true&objectDefinitionExternalReferenceCode=ABLE&objectEntryExternalReferenceCode=ATTACHMENT_FROM_USERS_COMPUTER_1",
         "label": "AttachmentFromUsersComputer1.png"
      },
      "name": "AttachmentFromUsersComputer1.png"
   }
}

    Note that the response doesn’t contain the fileBase64 encoding by default. See Getting the Attachment’s Content in the Response to learn more.

Execute Able_POST_FromUsersComputer2.sh to create an object entry with an attachment using the Upload Directly from the User's Computer Request Files option and the Show Files in Documents and Media option toggled on. Note that specifying a folder is unnecessary. The folder selection is based automatically on the company for company-scoped object definitions or the site for site-scoped object definitions.

./Able_POST_FromUsersComputer2.sh

Posting an Attachment Uploaded or Selected From The Documents and Media Item Selector

  1. Execute DocumentFolder_POST_ToSite.sh to create the folder to store the uploaded file. Use the site ID as a parameter. In this example, the site ID is 20117

    Tip

    Locate the site ID at Site Menu (Site Menu) → Configuration → Site Settings → Site Configuration under Platform.

    ./DocumentFolder_POST_ToSite.sh [site-id]

    The terminal should display a similar output.

    {
"actions" : {
   "subscribe" : {
      "method" : "PUT",
      "href" : "http://localhost:8080/o/headless-delivery/v1.0/document-folders/32258/subscribe"
   },
   "unsubscribe" : {
      "method" : "PUT",
      "href" : "http://localhost:8080/o/headless-delivery/v1.0/document-folders/32258/unsubscribe"
   },
   "get" : {
      "method" : "GET",
      "href" : "http://localhost:8080/o/headless-delivery/v1.0/document-folders/32258"
   },
   "replace" : {
      "method" : "PUT",
      "href" : "http://localhost:8080/o/headless-delivery/v1.0/document-folders/32258"
   },
   "update" : {
      "method" : "PATCH",
      "href" : "http://localhost:8080/o/headless-delivery/v1.0/document-folders/32258"
   },
   "delete" : {
      "method" : "DELETE",
      "href" : "http://localhost:8080/o/headless-delivery/v1.0/document-folders/32258"
   }
},
"creator" : {
   "additionalName" : "",
   "contentType" : "UserAccount",
   "familyName" : "Test",
   "givenName" : "Test",
   "id" : 20122,
   "name" : "Test Test"
},
"customFields" : [ ],
"dateCreated" : "2024-06-05T16:37:12Z",
"dateModified" : "2024-06-05T16:37:12Z",
"description" : "This folder stores the attachment files for this exercise.",
"externalReferenceCode" : "ABLE_FOLDER",
"id" : 32258,
"name" : "Able Folder",
"numberOfDocumentFolders" : 0,
"numberOfDocuments" : 0,
"siteId" : 20117,
"subscribed" : false
}

  2. Execute Able_POST_FromDocumentsAndMedia.sh. This creates an object entry with a Base64 file attached to it and places it in the recently created folder. Use the folder’s ERC and the site ID as parameters. In this example, the ERC is ABLE_FOLDER and the site ID is 20117.

    ./Able_POST_FromDocumentsAndMedia.sh [ERC] [site-id]

    Use the folder parameter to add the externalReferenceCode and the siteId to store the document.

    ...
"folder": {
   "externalReferenceCode": "'${1}'",
   "siteId": "'${2}'"
},
...
    Note

    If the siteId or the ERC are not included, null, or empty, the POST request still works, and the file is uploaded to the default site’s root folder.

    The terminal should display a similar output.

    {
"actions" : {
   "permissions" : {
      "method" : "GET",
      "href" : "http://localhost:8080/o/c/ables/32337/permissions"
   },
   "get" : {
      "method" : "GET",
      "href" : "http://localhost:8080/o/c/ables/32337"
   },
   "replace" : {
      "method" : "PUT",
      "href" : "http://localhost:8080/o/c/ables/32337"
   },
   "update" : {
      "method" : "PATCH",
      "href" : "http://localhost:8080/o/c/ables/32337"
   },
   "delete" : {
      "method" : "DELETE",
      "href" : "http://localhost:8080/o/c/ables/32337"
   }
},
"creator" : {
   "additionalName" : "",
   "contentType" : "UserAccount",
   "familyName" : "Test",
   "givenName" : "Test",
   "id" : 20122,
   "name" : "Test Test"
},
"dateCreated" : "2024-06-05T16:37:36Z",
"dateModified" : "2024-06-05T16:37:36Z",
"externalReferenceCode" : "ATTACHMENT_FROM_DOCS_AND_MEDIA",
"id" : 32337,
"keywords" : [ ],
"status" : {
   "code" : 0,
   "label" : "approved",
   "label_i18n" : "Approved"
},
"taxonomyCategoryBriefs" : [ ],
"docsAndMediaAttachment" : {
   "id" : 32332,
   "link" : {
      "href" : "/documents/20119/0/AttachmentFromDocumentsAndMedia.png/bbe75f48-04ce-2967-1721-973655b9a853?version=1.0&t=1717605455991&download=true&objectDefinitionExternalReferenceCode=ABLE&objectEntryExternalReferenceCode=ATTACHMENT_FROM_DOCS_AND_MEDIA",
      "label" : "AttachmentFromDocumentsAndMedia.png"
   },
   "name" : "AttachmentFromDocumentsAndMedia.png"
}
}
    Note

    Uploading a file with the same name as an existing file in the destination folder results in the new file being renamed with a unique sequential number in parentheses (i.e., Name (n).extension).

    Note that the response doesn’t contain the fileBase64 encoding by default. See Getting the Attachment’s Content in the Response to learn more.

Getting a List of All Entries

  1. Run Able_GET_FromCompany.sh to get a list of all entries.

    ./Able_GET_FromCompany.sh

    The response should include information about the attached file such as the id, a link where you can download it, its label, and its name.

    ...
"dateCreated" : "2024-06-05T16:37:26Z",
"dateModified" : "2024-06-05T16:37:26Z",
"externalReferenceCode" : "ATTACHMENT_FROM_USERS_COMPUTER_1",
"id" : 32268,
"keywords" : [ ],
"status" : {
"code" : 0,
"label" : "approved",
"label_i18n" : "Approved"
},
"taxonomyCategoryBriefs" : [ ],
"usersComputerAttachment1" : {
"id" : 32263,
"link" : {
   "href" : "/documents/32260/32262/AttachmentFromUsersComputer1.png/f0a02e6a-8eeb-d021-bfdd-82da1afab1cf?version=1.0&t=1717605446526&download=true&objectDefinitionExternalReferenceCode=ABLE&objectEntryExternalReferenceCode=ATTACHMENT_FROM_USERS_COMPUTER_1",
   "label" : "AttachmentFromUsersComputer1.png"
},
"name" : "AttachmentFromUsersComputer1.png"
}
...

    Note that the response contains the address for the files, but it doesn’t contain the fileBase64 encodings by default. See Getting the Attachment’s Content in the Response to learn more.

Updating an Object Entry With an Attachment

Use a PUT request to replace the entire object entry with the details provided in the API call. In this case, the same structure used to POST the object entry must be used with the PUT request, with alterations to the specific fields you wish to update.

Similarly, although a PATCH request would include only specific fields to be changed in the structure, you must ensure the PATCH structure and content match those used during creation too.

To alter an entry using a PUT request,

  1. Execute Able_PUT_ById.sh to change the external reference code and the name of the file attached to the object entry. Use the object entry ID as a parameter.

    In this example, the ID for the ATTACHMENT_FROM_USERS_COMPUTER_1 entry retrieved in the GET request is 32268.

    ./Able_PUT_ById.sh [Object-ID]

    A response displays the updated information for the object entry. Note that the response contains the address for the file, but it doesn’t contain the fileBase64 encoding by default. See Getting the Attachment’s Content in the Response to learn more.

  2. The external reference code is now ATTACHMENT_FROM_USERS_COMPUTER_1_ALTERED and the image is named AttachmentFromUsersComputer1Altered.png.

    "dateCreated" : "2024-06-05T16:37:26Z",
"dateModified" : "2024-06-05T16:38:11Z",
"externalReferenceCode" : "ATTACHMENT_FROM_USERS_COMPUTER_1_ALTERED",
...
   "link" : {
      "href" : "/documents/32260/32262/AttachmentFromUsersComputer1Altered.png/da5fe5a1-c36c-e016-846e-20720b7469a8?version=1.0&t=1717605491796&download=true&objectDefinitionExternalReferenceCode=ABLE&objectEntryExternalReferenceCode=ATTACHMENT_FROM_USERS_COMPUTER_1_ALTERED",
      "label" : "AttachmentFromUsersComputer1Altered.png"
   },
   "name" : "AttachmentFromUsersComputer1Altered.png"
}

Deleting an Object Entry With an Attachment

  1. Execute Able_DELETE_ById.sh to delete the object entry and its attachment. Use the object entry ID as a parameter.

    ./Able_DELETE_ById.sh [Object-ID]

  2. There is no content in the response.

Getting the Attachment’s Content in the Response

To get the Base64 encoded file in the response, you must request it as a nested field by using the nestedFields=[fieldName].fileBase64 query parameter. This avoids calculating the Base64 encoding if the user hasn’t requested it.

Execute this cURL command in your terminal to get the attachment’s content for the entry with the ATTACHMENT_FROM_USERS_COMPUTER_2 ERC:

curl \
   "http://localhost:8080/o/c/ables/by-external-reference-code/ATTACHMENT_FROM_USERS_COMPUTER_2?nestedFields=usersComputerAttachment2.fileBase64" \
   --request "GET" \
   --user "test@liferay.com:learn"

The terminal should display a similar output with the Base64 encoded file, its ID, link, label, and name.

...
"usersComputerAttachment2" : {
   "fileBase64" : "iVBORw0KG...kJggg==",
   "id" : 32283,
   "link" : {
   "href" : "/documents/20119/32281/AttachmentFromUsersComputer2.png/266a539c-506c-8273-96d2-15206933b993?version=1.0&t=1717605449655&download=true&objectDefinitionExternalReferenceCode=ABLE&objectEntryExternalReferenceCode=ATTACHMENT_FROM_USERS_COMPUTER_2",
   "label" : "AttachmentFromUsersComputer2.png"
   },
   "name" : "AttachmentFromUsersComputer2.png"
}

Getting the Attachment’s Folder in the Response

To get the folder where the Base64 encoded file is stored in the response, you must request it as a nested field by using the nestedFields=[fieldName].folder query parameter. This avoids unnecessary access to data.

Execute this cURL command in your terminal to get the folder for the entry with the ATTACHMENT_FROM_DOCS_AND_MEDIA ERC:

curl \
   "http://localhost:8080/o/c/ables/by-external-reference-code/ATTACHMENT_FROM_DOCS_AND_MEDIA?nestedFields=docsAndMediaAttachment.folder" \
   --request "GET" \
   --user "test@liferay.com:learn"

The terminal shows a similar output with the folder’s ERC and siteId where it’s located.

...
"docsAndMediaAttachment" : {
   "folder" : {
   "externalReferenceCode" : "ABLE_FOLDER",
   "siteId" : 20117
   },
...
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