Re: using APIs in fabric #fabric #fabric-questions #fabric-endorser


David Enyeart
 

Remember that chaincode execution is only a transaction simulation that builds a read/write set. The transaction doesn't get validated and committed until after it is ordered into a block. Therefore you don't want to call any external services that take action from a chaincode. Rather, your application can listen for the block commit events, and then take action for any validated and committed transactions.


"elmira" ---04/19/2021 07:54:35 AM---Hi, What kind of external services are we allowed to use in fabric? Can we use any APIs? Or we must

From: "elmira" <elmira.ebrahimi@...>
To: fabric@...
Date: 04/19/2021 07:54 AM
Subject: [EXTERNAL] [Hyperledger Fabric] using APIs in fabric #fabric-questions #fabric-endorser #fabric
Sent by: fabric@...





Hi,  What kind of external services are we allowed to use in fabric? Can we use any APIs? Or we must just use fabric SDK.  For example, an external service is a bank ATM API, and our transaction is calling the ATM withdrawal operation. ‍‍‍‍ZjQcmQRYFpfptBannerStart
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Hi,
 What kind of external services are we allowed to use in fabric? Can we use any APIs? Or we must just use fabric SDK.
 For example, an external service is a bank ATM API, and our transaction is calling the ATM withdrawal operation.
 We have defined in our policies that four endorsers must approve it. When the endorser nodes call that external service, are the withdrawal operations performed four times separately; and change the bank account's balance outside the blockchain each time? (so we have trouble in the commitment phase) How can we handle external calls?
I appreciate any help you can provide.




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