Overview
TUNA provides two functions for posting comments on articles:
- Short comments (≤280 characters): Stored entirely on-chain
- Long comments or comments with media: Preview stored on-chain, full content on Walrus
Function Signature
function createPostCommentTransaction(blobId: string, commentText: string): Transaction
Parameters
The Walrus blob ID of the article you’re commenting on.
The comment text. Must be 280 characters or less.
Move Call Structure
tx.moveCall({
target: `${PACKAGE_ID}::news_registry::post_comment`,
arguments: [
tx.object(REGISTRY_ID), // The news registry shared object
tx.pure.string(blobId), // Article blob ID
tx.pure.string(commentText), // Comment text (≤280 chars)
],
});
Usage Example
import { useSignAndExecuteTransactionBlock } from '@mysten/dapp-kit';
import { createPostCommentTransaction } from './lib/sui';
import { CONSTANTS } from './config';
function CommentForm({ blobId }: { blobId: string }) {
const [text, setText] = useState('');
const { mutate: signAndExecute } = useSignAndExecuteTransactionBlock();
const handleSubmit = () => {
if (text.length > CONSTANTS.SHORT_COMMENT_THRESHOLD) {
alert('Comment too long! Use the long comment feature.');
return;
}
const tx = createPostCommentTransaction(blobId, text);
signAndExecute(
{ transaction: tx },
{
onSuccess: (result) => {
console.log('Comment posted!', result.digest);
setText('');
},
}
);
};
return (
<div>
<textarea
value={text}
onChange={(e) => setText(e.target.value)}
maxLength={280}
/>
<p>{text.length}/280 characters</p>
<button onClick={handleSubmit}>Post Comment</button>
</div>
);
}
Function Signature
function createPostCommentWithBlobTransaction(
blobId: string,
previewText: string,
contentBlobId: string,
commentType: 'text_long' | 'media'
): Transaction
Parameters
The Walrus blob ID of the article you’re commenting on.
A preview of the comment (≤280 characters) that will be stored on-chain. This appears in feeds without requiring Walrus access.
The Walrus blob ID containing the full comment content. Upload your content to Walrus first and use the returned blob ID here.
The type of comment:
'text_long': Long text content'media': Comment with images, videos, or other media
Move Call Structure
tx.moveCall({
target: `${PACKAGE_ID}::news_registry::post_comment_with_blob`,
arguments: [
tx.object(REGISTRY_ID), // The news registry shared object
tx.pure.string(blobId), // Article blob ID
tx.pure.string(previewText), // Preview text (≤280 chars)
tx.pure.string(contentBlobId), // Walrus blob ID for full content
tx.pure.string(commentType), // 'text_long' or 'media'
],
});
Usage Example
import { useSignAndExecuteTransactionBlock } from '@mysten/dapp-kit';
import { createPostCommentWithBlobTransaction } from './lib/sui';
import { uploadToWalrus } from './lib/walrus';
function LongCommentForm({ blobId }: { blobId: string }) {
const [text, setText] = useState('');
const [isUploading, setIsUploading] = useState(false);
const { mutate: signAndExecute } = useSignAndExecuteTransactionBlock();
const handleSubmit = async () => {
setIsUploading(true);
try {
// Upload full content to Walrus
const contentBlobId = await uploadToWalrus({
text: text,
timestamp: Date.now(),
});
// Create preview (first 280 chars)
const preview = text.length > 280
? text.slice(0, 277) + '...'
: text;
// Create transaction
const tx = createPostCommentWithBlobTransaction(
blobId,
preview,
contentBlobId,
'text_long'
);
// Sign and execute
signAndExecute(
{ transaction: tx },
{
onSuccess: (result) => {
console.log('Long comment posted!', result.digest);
setText('');
},
}
);
} catch (error) {
console.error('Failed to upload to Walrus:', error);
alert('Failed to post comment');
} finally {
setIsUploading(false);
}
};
return (
<div>
<textarea
value={text}
onChange={(e) => setText(e.target.value)}
/>
<button onClick={handleSubmit} disabled={isUploading}>
{isUploading ? 'Uploading...' : 'Post Long Comment'}
</button>
</div>
);
}
Short comment stored entirely on-chain (≤280 characters)
Long text comment with preview on-chain and full content on Walrus
Comment containing images, videos, or other media files stored on Walrus
The 280-character threshold (CONSTANTS.SHORT_COMMENT_THRESHOLD) matches Twitter’s classic character limit and provides a good balance between on-chain storage costs and user experience.
Response
Both functions create a Comment object on-chain with the following properties:
- Unique comment ID
- Author’s address
- Timestamp
- Content (or preview + blob reference)
- Tip balance (initially 0)
Preview text must be 280 characters or less. The transaction will fail if the preview exceeds this limit.
Hybrid Storage Benefits
- Short comments: Fast, fully on-chain, no external dependencies
- Long comments: Cost-effective, leverages Walrus for large content
- Preview text: Users can see comments without accessing Walrus
- Media support: Share images and videos in comments
