Mdthbs

Is there a verb for listening stealthily?

Recursive calls to a function - why is the address of the parameter passed to it lowering with each call?

Why did Israel vote against lifting the American embargo on Cuba?

/bin/ls sorts differently than just ls

“Since the train was delayed for more than an hour, passengers were given a full refund.” – Why is there no article before “passengers”?

How was Lagrange appointed professor of mathematics so early?

Should man-made satellites feature an intelligent inverted "cow catcher"?

Is Bran literally the world's memory?

Why is one lightbulb in a string illuminated?

Is it OK if I do not take the receipt in Germany?

Can the van der Waals coefficients be negative in the van der Waals equation for real gases?

Coin Game with infinite paradox

Pointing to problems without suggesting solutions

Marquee sign letters

false 'Security alert' from Google - every login generates mails from 'no-reply@accounts.google.com'

Why not use the yoke to control yaw, as well as pitch and roll?

Will I be more secure with my own router behind my ISP's router?

A journey... into the MIND

Do chord progressions usually move by fifths?

tabularx column has extra padding at right?

What's the connection between Mr. Nancy and fried chicken?

Why do people think Winterfell crypts is the safest place for women, children & old people?

Assertions In A Mock Callout Test

Weaponising the Grasp-at-a-Distance spell

How to charge percentage of transaction cost?

1

Example:

uint public createPostCost = 0.0003 ether;



function createPost(bytes32 _post) 

    public payable {

        require(msg.value >= createPostCost);

        Post memory newPost;

        newPost.post = _post;

    }

Within a discussion forum dapp, the current implementation charges users a set fee per post created. I would like the charge to be dynamic, say 10% of the gas cost of the transaction. Is this possible to implement in the contract? Or is this something for front-end web3 to handle?

solidity web3js contract-development gas gas-limit

share|improve this question

edited 7 hours ago

shane

2,4524832

asked 7 hours ago

Jaren LJaren L

335

add a comment | 

1

Example:

uint public createPostCost = 0.0003 ether;



function createPost(bytes32 _post) 

    public payable {

        require(msg.value >= createPostCost);

        Post memory newPost;

        newPost.post = _post;

    }

Within a discussion forum dapp, the current implementation charges users a set fee per post created. I would like the charge to be dynamic, say 10% of the gas cost of the transaction. Is this possible to implement in the contract? Or is this something for front-end web3 to handle?

solidity web3js contract-development gas gas-limit

share|improve this question

edited 7 hours ago

shane

2,4524832

asked 7 hours ago

Jaren LJaren L

335

add a comment | 

Example:

uint public createPostCost = 0.0003 ether;



function createPost(bytes32 _post) 

    public payable {

        require(msg.value >= createPostCost);

        Post memory newPost;

        newPost.post = _post;

    }

Within a discussion forum dapp, the current implementation charges users a set fee per post created. I would like the charge to be dynamic, say 10% of the gas cost of the transaction. Is this possible to implement in the contract? Or is this something for front-end web3 to handle?

solidity web3js contract-development gas gas-limit

share|improve this question

edited 7 hours ago

shane

2,4524832

asked 7 hours ago

Jaren LJaren L

335

uint public createPostCost = 0.0003 ether;



function createPost(bytes32 _post) 

    public payable {

        require(msg.value >= createPostCost);

        Post memory newPost;

        newPost.post = _post;

    }

share|improve this question

edited 7 hours ago

shane

2,4524832

asked 7 hours ago

Jaren LJaren L

335

share|improve this question

edited 7 hours ago

shane

2,4524832

asked 7 hours ago

Jaren LJaren L

335

edited 7 hours ago

shane

2,4524832

edited 7 hours ago

shane

2,4524832

asked 7 hours ago

Jaren LJaren L

335

asked 7 hours ago

Jaren LJaren L

335

1 Answer
1

active

oldest

votes

3

Yes, you can let the charge be a function of the gas of the transaction. You would do something like this:

uint256 charge = gasleft() / 10;

This is sensitive and you should know that gasleft() returns the amount of gas available at that point in the execution. Therefore, if you call gasleft() at the beginning of a function, the number will be higher than at the end of the function.

Additionally, someone may send a lot of unnecessary gas, so they could end up paying a lot.

My opinion is that it is best to handle this on the front-end.

Edit

If you are trying to take into account the gasPrice, you can use tx.gasprice. See here for more information.

share|improve this answer

edited 7 hours ago

answered 7 hours ago

shaneshane

2,4524832

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  Psst, msg.gas has been removed and replaced by gasleft as per solidity.readthedocs.io/en/latest/…
  
  – Lauri Peltonen
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Ahh yes. Thank you.
  
  – shane
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Ah that makes sense. If I made a require to check the msg.value >= 10% of tx.gasprice, would that work? Would there be discrepancies between generating the web3 function call price + value and the contract value?
  
  – Jaren L
  4 hours ago
  
  
  

  
  
  
  

add a comment | 

Your Answer

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "642"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fethereum.stackexchange.com%2fquestions%2f69960%2fhow-to-charge-percentage-of-transaction-cost%23new-answer', 'question_page');
}
);

Post as a guest

Name

Email

Required, but never shown

3

Yes, you can let the charge be a function of the gas of the transaction. You would do something like this:

uint256 charge = gasleft() / 10;

This is sensitive and you should know that gasleft() returns the amount of gas available at that point in the execution. Therefore, if you call gasleft() at the beginning of a function, the number will be higher than at the end of the function.

Additionally, someone may send a lot of unnecessary gas, so they could end up paying a lot.

My opinion is that it is best to handle this on the front-end.

Edit

If you are trying to take into account the gasPrice, you can use tx.gasprice. See here for more information.

share|improve this answer

edited 7 hours ago

answered 7 hours ago

shaneshane

2,4524832

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  Psst, msg.gas has been removed and replaced by gasleft as per solidity.readthedocs.io/en/latest/…
  
  – Lauri Peltonen
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Ahh yes. Thank you.
  
  – shane
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Ah that makes sense. If I made a require to check the msg.value >= 10% of tx.gasprice, would that work? Would there be discrepancies between generating the web3 function call price + value and the contract value?
  
  – Jaren L
  4 hours ago
  
  
  

  
  
  
  

add a comment | 

3

Yes, you can let the charge be a function of the gas of the transaction. You would do something like this:

uint256 charge = gasleft() / 10;

This is sensitive and you should know that gasleft() returns the amount of gas available at that point in the execution. Therefore, if you call gasleft() at the beginning of a function, the number will be higher than at the end of the function.

Additionally, someone may send a lot of unnecessary gas, so they could end up paying a lot.

My opinion is that it is best to handle this on the front-end.

Edit

If you are trying to take into account the gasPrice, you can use tx.gasprice. See here for more information.

share|improve this answer

edited 7 hours ago

answered 7 hours ago

shaneshane

2,4524832

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  Psst, msg.gas has been removed and replaced by gasleft as per solidity.readthedocs.io/en/latest/…
  
  – Lauri Peltonen
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Ahh yes. Thank you.
  
  – shane
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Ah that makes sense. If I made a require to check the msg.value >= 10% of tx.gasprice, would that work? Would there be discrepancies between generating the web3 function call price + value and the contract value?
  
  – Jaren L
  4 hours ago
  
  
  

  
  
  
  

add a comment | 

Yes, you can let the charge be a function of the gas of the transaction. You would do something like this:

uint256 charge = gasleft() / 10;

This is sensitive and you should know that gasleft() returns the amount of gas available at that point in the execution. Therefore, if you call gasleft() at the beginning of a function, the number will be higher than at the end of the function.

Additionally, someone may send a lot of unnecessary gas, so they could end up paying a lot.

My opinion is that it is best to handle this on the front-end.

Edit

If you are trying to take into account the gasPrice, you can use tx.gasprice. See here for more information.

share|improve this answer

edited 7 hours ago

answered 7 hours ago

shaneshane

2,4524832

share|improve this answer

edited 7 hours ago

answered 7 hours ago

shaneshane

2,4524832

answered 7 hours ago

shaneshane

2,4524832

answered 7 hours ago

shaneshane

2,4524832