What is the gas limit for a view function call *not made from a contract*?

Question

So this question seems trivial but I can't find any comprehensive answer, though reading through:

• Is there a gas limit for view requests?
• Why view/pure functions need gas?
• Exceeds block gas limit error to call view functions
• Can Solidity constant functions be arbitrarily complex?
• Solidity Exceeds block gas limit during Mocha Tests with Ganache-cli
• Block Gas Limit Doubt
• Gas consumption of a view public function
• How to interpret the "Gas Limit" column on etherscan's internal txns view?
• High gas consumption when using `staticcall` on a non-view/pure function

My question is as follows:

• I can call estimateGas to estimate the gas needed to call one of my functions from ethers.js
• What is the limit gas for my function?

Context: I am working on a on-chain NFT project and the tokenURI method is a bit complex. I don't understand if this is a problem. And how much gas maximum it should have?

Answer 1

What is the limit gas for my function?

estimateGas will return a reasonably accurate value for your tokenURI method.

(If your tokenURI method is very contrived/variable, be aware of What are the limitations to estimateGas and when would its estimate be considerably wrong?)

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tokenURI method is a bit complex. I don't understand if this is a problem.

Users generally do not invoke the tokenURI method so you are usually OK.

The effect of any expensive smart contract function (including tokenURI) is less on-chain composability/interoperability with that function, possibly the whole contract.

A web2 analogy might be calling a slow, unreliable, or paid API: developers will avoid calling those APIs in preference for something faster and reliable.

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And how much gas maximum it should have?

We can say that a very expensive tokenURI method would be one that consumes half the block gas limit. Even 10% of the block gas limit seems high, so I would aim for lower than 10%.

Even though tokenURIis usually only called off-chain so that its gas usage doesn't matter as much, I would not underestimate the chances that there may be creative uses of tokenURI on-chain in the future, so I would still try to be reasonable about its gas consumption.