How to wait programatically until block is added in the network?

Question

Hi,

Currently, I am working on streams. I have used the following code to publish data in the stream using node.js. 

packet = new Buffer(data[0]).toString("hex")

mc.publish({ stream: "datastream", key: "through", data: packet }).then(x => {

sucess++;

//total_size += passedSize;

callback(null, sucess);

 

}).catch(y => {

//sucess++;

//total_size += passedSize;

callback(null, sucess);

})

Here, I want to find the latency of adding data in the block for publishing data in the stream. But I think in this code, the callback is returned when data is added as an unspent transaction. But I want to wait till it added in the block. How to do that? any help? 

here is the parameter: 

chain-protocol = multichain           
chain-description = MultiChain buchain  
root-stream-name = root               
root-stream-open = true               
chain-is-testnet = false               
target-block-time = 2                 
maximum-block-size = 1000000000         

# Global permissions

anyone-can-connect = false              
anyone-can-send = false                 
anyone-can-receive = false             
anyone-can-receive-empty = true        
anyone-can-create = false             
anyone-can-issue = false              
anyone-can-mine = false                
anyone-can-activate = false             
anyone-can-admin = false                
support-miner-precheck = true          
allow-arbitrary-outputs = false      
allow-p2sh-outputs = true              
allow-multisig-outputs = true          

setup-first-blocks = 60                 
mining-diversity = 0.3                  
admin-consensus-upgrade = 0.5          
admin-consensus-admin = 0.5             
admin-consensus-activate = 0.5         
admin-consensus-mine = 0.5              
admin-consensus-create = 0.0           
admin-consensus-issue = 0.0           

lock-admin-mine-rounds = 10           
mining-requires-peers = true            
mine-empty-rounds = 10                  
mining-turnover = 0.5                 

initial-block-reward = 0               
first-block-reward = -1                 
reward-halving-interval = 52560000      
reward-spendable-delay = 1              
minimum-per-output = 0                  
maximum-per-output = 100000000000000   
minimum-relay-fee = 0                   
native-currency-multiple = 100000000   

skip-pow-check = false                
pow-minimum-bits = 1                    
target-adjust-freq = -1                 
allow-min-difficulty-blocks = false   

only-accept-std-txs = true              
max-std-tx-size = 100000000             
max-std-op-returns-count = 1024         
max-std-op-return-size = 2097152        
max-std-op-drops-count = 5              
max-std-element-size = 32768          

Thanks in advance.

Answer 1

You can use the blocknotify runtime parameter to trigger an external command when a new block comes in:

https://www.multichain.com/developers/runtime-parameters/

This can then query to check if the stream items were confirmed.

Comments

Thanks for your comment. I want to check within the same code block of submitting stream data instead of triggering another script. Is there any way to do that programmatically?

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The item will not be confirmed immediately, there will likely be a delay of a few seconds. But if you want you can use the script to keep checking, say once per second, until the item is confirmed, in a polling kind of pattern.

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Thanks for your suggestions. I am trying to use getWalletTransaction and check confirmation > 0 property to confirm that transaction is added in the block or not. Is it the right way?

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Yes, it's one way to do it. If the node is subscribed to the stream you can also use the regular stream querying commands.

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Thanks for your help.