Casper Casper Association | Writing On-Chain Code, 4 Nov 2022

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From YouTube: Casper Association | Writing On-Chain Code | 14. Calling Contracts with Session Arguments

Description

In this video, we will see how to call contracts using session arguments.

The Casper client put-deploy command allows you to do this with the --session-arg option.

Reference documentation:
https://docs.casperlabs.io/dapp-dev-guide/writing-contracts/calling-contracts/#calling-contracts-with-session-args

Reference contract code:
https://github.com/casper-ecosystem/counter/tree/count_inc_with_args
The command used in this example to call a contract using arguments is:
casper-client put-deploy \
--node-address http://135.181.208.231:7777 \
--chain-name casper-test \
--secret-key /Users/iulia/KEYS/secret_key.pem \
--payment-amount 100000000 \
--session-hash hash-cc752f2cc0eb235dc17294b4368cbba3735a7ea5260ac45155473ea5971c1bef \
--session-entry-point "counter_inc" \
--session-arg "amount:i32='20'"

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In this video we will see how to call contracts using session arguments. Sometimes you may need to pass in information using arguments when calling contract entry points.

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The put deploy allows you to do this with the session Arc option. This example demonstrates how to call a contract using arguments. Let's look at the contract and the test that demonstrate how to call an entry point. Given an argument here, we have modified the counter ink entry point to take in the amount that we want to increment with.

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In the test, when we create a contract increment request, we specify the amount argument.

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Now, let's run the test to make sure that it all works correctly.

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Since the tests are successful, let's send the put deploy to the network. We will install this modified counter contract to be able to call the counter ink entry point with an argument.

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Here is the put deploy call where we specify the package name, counter package name, the session entry point counter ink and the argument to be amount equal to 50.

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Let's check the value of count, we expect it to have increased from 0 to 50.. The value is correct, so we were able to call the counter in entry point with the argument passed in until now, we have seen several ways to invoke contract code. In the next video. We will look at how to call a versioned contract.