WhatsApp Flows

Media upload components

WhatsApp does not guarantee that data (such as images, videos, or documents) shared with you by your customers is non-malicious. Make sure to implement appropriate risk mitigations when processing such data (for example, using well-tested and up-to-date media and document processing libraries).

Media upload components are not supported by the On-Premise API client. Please refer to the deprecation announcent and learn how to migrate to Cloud API.

Flow JSON components

Two components can be used to ask users to upload media

  • PhotoPicker: allows uploading media from camera or gallery
  • DocumentPicker: allows uploading media from files or gallery

PhotoPicker

Supported starting with Flow JSON version 4.0

参数说明
type
(required)
string
 PhotoPicker
name
(required)
string
 Component's name. Should be distinct among all components on a screen.
label
(required)
string

Header text for the component.

Dynamic "${data.label}" OR "${screen.<screen_id>.data.label}"

Max length: 80 characters
description
string

Body text for the component.

Dynamic "${data.description}" OR "${screen.<screen_id>.data.description}"

Max length: 300 characters
photo-source
enum

Specifies the source where the image can be selected from.

Values: {'camera_gallery', 'camera', 'gallery'}
Default: 'camera_gallery'

  • camera_gallery: user can select from gallery or take a photo
  • gallery: user can select only from gallery
  • camera: user can only take a photo

max-file-size-kb
Integer

Specifies the maximum file size (in kibibytes) that can be uploaded.

Default value: 25600 (25 MiB)
Allowed range: [1, 25600]
min-uploaded-photos
Integer

Specifies the minimum number of photos that are required.

This property determines whether the component is optional (set to 0) or required (set above 0).

Default value: 0
Allowed range: [0, 30]

Note: Above limits apply if media files are sent to the endpoint via "data_exchange" action. For images or documents sent as part of the response message, no more of 10 files can be attached. Additionally, the aggregated size of them cannot exceed 100 MiB.

max-uploaded-photos
Integer

Specifies the maximum number of photos that can be uploaded.

Default value: 30
Allowed range: [1, 30]

Note: Above limits apply if media files are sent to the endpoint via "data_exchange" action. For images or documents sent as part of the response message, no more of 10 files can be attached. Additionally, the aggregated size of them cannot exceed 100 MiB.

enabled
Boolean | String

Specifies if user interaction will be enabled on the component(true = enabled, false = disabled).

Dynamic "${data.is_enabled}" OR "${screen.<screen_id>.data.is_enabled}"

Default: true
visible
Boolean | String

Specifies if the component will be visible on the screen(true = visible, false = hidden).

Dynamic "${data.is_visible}" OR ${screen.<screen_id>.data.visible}"

Default: true
error-message
String | Object

Specifies errors when processing the images.

Dynamic "${data.error_message}"
  • String: specifies a generic error for the whole component.
  • Object: specifies image specific errors. Only use with dynamic data as media id must be supplied

The format for Object is the following:
{"media_id_1" : "error_message 1", "media_id_2" : "error_message 2"}

Check the endpoint handling section below to find out more about the media ids.

Example

Note that the image selection behaviour is mocked in this preview. The actual behaviour on device will be similar to the image selection in WhatsApp chats.


Limitations and Restrictions

The table below outlines the constraints associated with the PhotoPicker component.

Constraint Validation error

min-uploaded-photos should not exceed max-uploaded-photos

"min-uploaded-photos" cannot be greater than "max-uploaded-photos" for PhotoPicker component ${component_name}.

PhotoPicker cannot be initialised using Form init-values

Invalid value found for property at ${path}. "init-values" property should not contain a value for PhotoPicker component.

Only 1 PhotoPicker is allowed per screen

You can only have a maximum of 1 component of type PhotoPicker per screen.


Using both PhotoPicker and DocumentPicker components on a single screen is not allowed.

You can only have a maximum of 1 component of type PhotoPicker or DocumentPicker per screen.


The PhotoPicker is not allowed in the navigate action payload.


To access the component's value from a different screen, you can utilize Global Dynamic Referencing.

The PhotoPicker component's value is not allowed in the payload of the navigate action.

The PhotoPicker component is restricted to top-level usage within the payloads of the data_exchange or complete action.


Valid:

"on-click-action": 
{
   "name": "data_exchange",
   "payload": 
    {
      "media": "${form.photo_picker}"
    }
}

Invalid:

"on-click-action":
{
  "name": "data_exchange",
  "payload": 
   {
    "media": {"photo": "${form.photo_picker}"}
   }
}

The PhotoPicker can only be used as the value of a top-level string property in the action payload.

No more than 10 images or documents can be sent as part of the response message.

Additionally, the maximum aggregated size of attached images or documents cannot exceed 100 MiB.

DocumentPicker

Supported starting with Flow JSON version 4.0

参数说明
type
(required)
string
 DocumentPicker
name
(required)
string
 Component's name. Should be distinct among all components on a screen.
label
(required)
string

Header text for the component.

Dynamic "${data.label}" OR "${screen.<screen_id>.data.label}"

Max length: 80 characters
description
string

Body text for the component.

Dynamic "${data.description}" OR "${screen.<screen_id>.data.description}"

Max length: 300 characters
max-file-size-kb
Integer

Specifies the maximum file size (in kibibytes) that can be uploaded.

Default value: 25600 (25 MiB)
Allowed range: [1, 25600]
min-uploaded-documents
Integer

Specifies the minimum number of documents that are required.

This property determines whether the component is optional (set to 0) or required (set above 0).

Default value: 0
Allowed range: [0, 30]

Note: Above limits apply if media files are sent to the endpoint via "data_exchange" action. For images or documents sent as part of the response message, no more of 10 files can be attached. Additionally, the aggregated size of them cannot exceed 100 MiB.

max-uploaded-documents
Integer

Specifies the maximum number of documents that can be uploaded.

Default value: 30
Allowed range: [1, 30]

Note: Above limits apply if media files are sent to the endpoint via "data_exchange" action. For images or documents sent as part of the response message, no more of 10 files can be attached. Additionally, the aggregated size of them cannot exceed 100 MiB.

allowed-mime-types
Array <string>

Specifies which document mime types can be selected. If it contains “image/jpeg”, picking photos from the gallery will be available as well.

Default: Any document from the supported mime types can be selected

Supported values:
1. application/gzip
2. application/msword
3. application/pdf
4. application/vnd.ms-excel
5. application/vnd.ms-powerpoint
6. application/vnd.oasis.opendocument.presentation
7. application/vnd.oasis.opendocument.spreadsheet
8. application/vnd.oasis.opendocument.text
9. application/vnd.openxmlformats-officedocument.presentationml.presentation
10. application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
11. application/vnd.openxmlformats-officedocument.wordprocessingml.document
12. application/x-7z-compressed
13. application/zip
14. image/avif
15. image/gif
16. image/heic
17. image/heif
18. image/jpeg
19. image/png
20. image/tiff
21. image/webp
22. text/plain
23. video/mp4
24. video/mpeg

Note: some old Android and iOS OS versions don’t understand all mime types above. As a result, a user might be able to select a file with a different mime type to the ones specified.

enabled
Boolean | String

Specifies if user interaction will be enabled on the component(true = enabled, false = disabled).

Dynamic "${data.is_enabled}" OR "${screen.<screen_id>.data.is_enabled}"

Default: true
visible
Boolean | String

Specifies if the component will be visible on the screen(true = visible, false = hidden).

Dynamic "${data.is_visible}" OR ${screen.<screen_id>.data.visible}"

Default: true
error-message
String | Object

Specifies errors when processing the documents.

Dynamic "${data.error_message}"
  • String: specifies a generic error for the whole component.
  • Object: specifies document specific errors. Only use with dynamic data as media id must be supplied

The format for Object is the following:
{"media_id_1" : "error_message 2", "media_id_2" : "error_message 2"}

Check the endpoint handling section below to find out more about the media ids.

Example

Note that the document selection behaviour is mocked in this preview. The actual behaviour on device will be similar to the document selection in WhatsApp chats.

Limitations and Restrictions

The table below outlines the constraints associated with the DocumentPicker component.

Constraint Validation error

min-uploaded-documents should not exceed max-uploaded-documents

"min-uploaded-documents" cannot be greater than "max-uploaded-documents" for DocumentPicker component ${component_name}.

DocumentPicker cannot be initialised using Form init-values

Invalid value found for property at ${path}. "init-values" property should not contain a value for DocumentPicker component.

Only 1 DocumentPicker is allowed per screen

You can only have a maximum of 1 component of type DocumentPicker per screen.

Using both PhotoPicker and DocumentPicker components on a single screen is not allowed.

You can only have a maximum of 1 component of type PhotoPicker or DocumentPicker per screen.


The DocumentPicker is not allowed in the navigate action payload.


To access the component's value from a different screen, you can utilize Global Dynamic Referencing.

The DocumentPicker component's value is not allowed in the payload of the navigate action.

The DocumentPicker component is restricted to top-level usage within the payloads of the data_exchange or complete action.


Valid:

"on-click-action": 
{
   "name": "data_exchange",
   "payload": 
    {
      "media": "${form.document_picker}"
    }
}

Invalid:

"on-click-action":
{
  "name": "data_exchange",
  "payload": 
   {
    "media": {"document": "${form.document_picker}"}
   }
}

The DocumentPicker can only be used as the value of a top-level string property in the action payload.

No more than 10 images or documents can be sent as part of the response message.

Additionally, the maximum aggregated size of attached images or documents cannot exceed 100 MiB.

Handling media

Endpoint

Media uploaded by the users are temporarily stored in WhatsApp CDN. Files are encrypted using AES256-CBC+HMAC-SHA256+pkcs7 cryptographic algorithms.

In your endpoint implementation, you must download, decrypt, and validate each media file.

Here’s a payload example for a photo or document.

"photo_picker":[{
     "media_id": "790aba14-5f4a-4dbd-aa9e-0d75401da14b",
     "cdn_url": "https://mmg.whatsapp.net/v/redacted",
     "file_name": "IMG_5237.jpg"
     "encryption_metadata": {
       "encrypted_hash": "/QvkBvpBED2q2AHPIFuhXfLpkn22zj2kO6ggzjvhHv0=",
       "iv": "5SHjLrrsfPXTSJTcbrVSkg==",
       "encryption_key": "lPa4SXcWbk3sy2so3OxjyXmpV4aE6CcIKd+4byr5hBw=",
       "hmac_key": "15l+E9Z5gcL15WH9OQ8GgK7VVCKkfbVigoSiM9djvGU=",
       "plaintext_hash": "AOF2dHXVEpm9efk9udNy3R1cUJWnpjFwQKGBEdALqXI="
     }]

Decrypting and validating media

The files stored in WhatsApp CDN contain the encrypted media and the first 10 bytes of the HMAC-SHA256 (concatenated at the end). For reference, cdn_file = ciphertext & hmac10

Perform the following steps to decrypt the media:
  1. Download cdn_file file from cdn_url
  2. Make sure SHA256(cdn_file) == enc_hash
  3. Validate HMAC-SHA256
    1. Calculate HMAC with hmac_key, initialization vector (encryption_metadata.iv) and ciphertex
    2. Make sure first 10 bytes == hmac10
  4. Decrypt media content
    1. Run AES with CBC mode and initialization vector (encryption_metadata.iv) on ciphertex
    2. Remove padding (AES256 uses blocks of 16 bytes, padding algorithm is pkcs7). We’ll call this decrypted_media
  5. Validate the decrypted media
    • Make sure SHA256(decrypted_media) = plaintext_hash

Response message (Cloud API)

Media can be received in the response message webhook.

Here’s a truncated example using PhotoPicker (same structure for DocumentPicker)

{
    "nfm_reply": {
        // [... redacted ... ]
        "response_json": {
            "photo_picker": [
                {
                    "file_name": "IMG_5237.jpg",
                    "mime_type": "image/jpeg",
                    "sha256": "PqHgadp8cJ/N6mvAYGNMxhs9Ra5hbZFcctCtCClXsMU=",
                    "id": "3631120727156756"
                }
            ],
            "flow_token": "xyz",
            "name": "John"
        }
    }
}

The media can be downloaded following the same steps as for regular image and document messages.

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