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Building GraphQL APIs on Ethereum

Nader Dabit on May 04, 2021

The number of production dapps continues to explode and the demand for developers building with Solidity and other blockchain languages continues t...
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Cameren Dolecheck •

Nice tutorial, thank you for creating high quality blockchain related tutorials on Dev.to!

I had not heard of The Graph until recently. What it allows to be built with relative ease is quite cool. The UI design of the application is great, too.

Maybe as a follow up, or a link to an existing explanation, it would be helpful to get more explanation on what's going on in mapping.ts.

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Roberto Cantu •

Thanks for the tutorial!

One thing I had to change: I couldn't get yarn deploy to work, so I went with the CLI command provided from The Graph UI graph deploy --product hosted-service <GitHub_Username>/<Subgraph_name>

Otherwise, the tutorial worked great!

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bilykdmytro • • Edited

Thank you for tutorial!
I think for initializing Zora contract we need to use / instead of \ at
graph init --from-contract 0xabEFBc9fD2F806065b4f3C237d4b59D9A97Bcac7 --network mainnet / --contract-name Token --index-events

At least I had to do it on Windows.

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Axel Masson •

Hello ! I'm getting Compile data source: Token => build\Token\Token.wasm

  • Compile subgraphERROR TS2322: Type 'generated/schema/Token | null' is not assignable to type 'generated/schema/Token'.

token.contentURI = event.params._uri;

 in src/mapping.ts(14,3)

for all the function that uses or load Token do you have any idea on why ?
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Nader Dabit •

Hey, unsure what happened, maybe there was an update to the CLI, but I just fixed the mappings and it should work now, sorry for the inconvenience!

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Friendly Tin Man • • Edited

Hi Nader!
The command "graph build" failed to compile data source mapping. This was caused by the error "Type 'Bytes' is not assignable to type 'string'."

This error pops up in two places:

  1. inside mapping.ts function "handleTokenIPFSPathUpdated",
    entity.indexedTokenIPFSPath = event.params.indexedTokenIPFSPath

  2. inside mapping.ts function "handleMinted",
    entity.indexedTokenIPFSPath = event.params.indexedTokenIPFSPath

How can I fix this issue?

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Sonia Joseph •

I'm also getting this issue. Any updates on progress?

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Matej Leško •

Thank you!!!! It is very interesting :) I like you omit basic stuff and go to the core

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Rafael Fuentes •

Eres el mejor! Estoy aprendiendo mucho gracias a ti.

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Wooj •

great tutorial dude! really enjoyed the content

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Serdar Senay •

I was having an issue with graph auth stage, getting an error Error: Error storing deploy key: Invalid URL

Solution was to run this command instead:
graph auth --product hosted-service

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Matt Lim •

FYI I needed to run yarn add @graphprotocol/graph-ts before graph build to make the build work

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Darrius Singleton •

Is GRT limited to just Ethereum based queries or can it be used for other protocols like Solana?

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orangeagain •

There Is Free Geth Graphql: querymaid.com/