# 🛠️ Builders **URL:** https://forum.flow.com/c/builders/37.md?page=3 [Latest](https://forum.flow.com/latest.md) · [Categories](https://forum.flow.com/categories.md) · [Tags](https://forum.flow.com/tags.md) **Page:** 4 --- ## [FLIP: Capability Controllers](https://forum.flow.com/t/flip-capability-controllers/2796)
**Author:** [@TheOneSock](https://forum.flow.com/u/TheOneSock)\ **Replies:** 0\ **Last updated:** [February 8, 2022, 11:02pm UTC](https://forum.flow.com/t/flip-capability-controllers/2796 "2022-02-08T23:02:19Z")
Hi everyone, I would be really interested in your opinion of this FLIP: Capability Controllers. The FLIP argues that the current system of creating, sharing and managing cadence capabilities is unwieldy and difficult t… --- ## [Access control in Cadence contract](https://forum.flow.com/t/access-control-in-cadence-contract/2752)
**Author:** [@p1xelch1ck](https://forum.flow.com/u/p1xelch1ck)\ **Replies:** 5\ **Last updated:** [February 5, 2022, 5:51am UTC](https://forum.flow.com/t/access-control-in-cadence-contract/2752 "2022-02-05T05:51:02Z")
Hi, I’m following flow tutorials and need help with contract level access controls. Example: I want to extend ExampleNFT to have a flag that can be set only by the NFT’s owner but read by everyone. I added a pub var … --- ## [Programming on Cadence](https://forum.flow.com/t/programming-on-cadence/2776)
**Author:** [@vusotsku](https://forum.flow.com/u/vusotsku)\ **Replies:** 1\ **Last updated:** [February 3, 2022, 4:57pm UTC](https://forum.flow.com/t/programming-on-cadence/2776 "2022-02-03T16:57:48Z")
Good afternoon. Are there other options for creating smart contracts, making transactions and creating NFTs other than Flow Playground? Or Playground was created not only for educational purposes? Thank you for your rep… --- ## [Sending Multiple & Delayed Transaction](https://forum.flow.com/t/sending-multiple-delayed-transaction/2771)
**Author:** [@Tanjiro](https://forum.flow.com/u/Tanjiro)\ **Replies:** 2\ **Last updated:** [February 3, 2022, 10:47am UTC](https://forum.flow.com/t/sending-multiple-delayed-transaction/2771 "2022-02-03T10:47:32Z")
Is it possible to sign multiple transactions in a Batch and have one delayed? Batch Transaction Scenario: Instantly - i want to mint an NFT today Wait - Send it to another wallet in 30 days I am not sure there is an… --- ## [Using ExecuteScriptAtLatestBlock to read state](https://forum.flow.com/t/using-executescriptatlatestblock-to-read-state/2765)
**Author:** [@tnugent](https://forum.flow.com/u/tnugent)\ **Replies:** 1\ **Last updated:** [February 1, 2022, 5:52pm UTC](https://forum.flow.com/t/using-executescriptatlatestblock-to-read-state/2765 "2022-02-01T17:52:46Z")
Hi there, Can anyone provide me an example script to demonstrate how ExecuteScriptAtLatestBlock can be used to read variables from an existing contract? I understand the method can be used for this, but none of the exam… --- ## [There is an urgent need to review Dapp!?](https://forum.flow.com/t/there-is-an-urgent-need-to-review-dapp/2742)
**Author:** [@VsamuelC](https://forum.flow.com/u/VsamuelC)\ **Replies:** 1\ **Last updated:** [January 24, 2022, 1:46pm UTC](https://forum.flow.com/t/there-is-an-urgent-need-to-review-dapp/2742 "2022-01-24T13:46:20Z")
I have learned in the DAPP Construction section of the official document that DAPP can only be deployed after review by the FLOW team when deployed to the main network. I only have one NonFungibleToken contract and one F… --- ## [NFT with IPFS](https://forum.flow.com/t/nft-with-ipfs/2701)
**Author:** [@sylv1un](https://forum.flow.com/u/sylv1un)\ **Replies:** 2\ **Last updated:** [January 21, 2022, 9:07am UTC](https://forum.flow.com/t/nft-with-ipfs/2701 "2022-01-21T09:07:31Z")
Hello everyone, I followed the “How to Create NFTs Like NBA Top Shot With Flow and IPFS” tutorial using file storage via IPFS (Pinata), but there are things bothering me and I will need your help to clear up a few point… --- ## [Cadence Contract update or Remove issue](https://forum.flow.com/t/cadence-contract-update-or-remove-issue/2734)
**Author:** [@saadtroon](https://forum.flow.com/u/saadtroon)\ **Replies:** 1\ **Last updated:** [January 20, 2022, 2:34pm UTC](https://forum.flow.com/t/cadence-contract-update-or-remove-issue/2734 "2022-01-20T14:34:03Z")
I am trying to update or remove contract but unable to do so. Any suggestion would be appreciable. You can see remove contract transaction below: https://testnet.flowscan.org/transaction/a56c4838188112c59890664013945e3c… --- ## [Design question - finding resource owner](https://forum.flow.com/t/design-question-finding-resource-owner/2694)
**Author:** [@p1xelch1ck](https://forum.flow.com/u/p1xelch1ck)\ **Replies:** 4\ **Last updated:** [January 17, 2022, 4:03pm UTC](https://forum.flow.com/t/design-question-finding-resource-owner/2694 "2022-01-17T16:03:02Z")
Hey, I started to play with Flow and Cadence and need some help understanding the architecture. I want create NFTs of type NoobieNFT and give it away to my friends, who will in turn give it to their friends etc. At an… --- ## [Sell kittyItems transaction failed](https://forum.flow.com/t/sell-kittyitems-transaction-failed/2470)
**Author:** [@sylv1un](https://forum.flow.com/u/sylv1un)\ **Replies:** 8\ **Last updated:** [January 14, 2022, 6:37pm UTC](https://forum.flow.com/t/sell-kittyitems-transaction-failed/2470 "2022-01-14T18:37:07Z")
Hi, I run the kittyItems project (https://github.com/onflow/kitty-items) on flow emulator, I deployed all the contracts on “account-emulator” and I created another account on which I setup a vault fusd, I minted fusd on… --- ## [Moving a Ethereum mainnet NFT project into FLOW](https://forum.flow.com/t/moving-a-ethereum-mainnet-nft-project-into-flow/2659)
**Author:** [@Otium](https://forum.flow.com/u/Otium)\ **Replies:** 2\ **Last updated:** [January 3, 2022, 5:06pm UTC](https://forum.flow.com/t/moving-a-ethereum-mainnet-nft-project-into-flow/2659 "2022-01-03T17:06:00Z")
Is there a way or case studies of NFT projects moving from ETH into Flow? --- ## [Timestamp to date](https://forum.flow.com/t/timestamp-to-date/2662)
**Author:** [@beppeben](https://forum.flow.com/u/beppeben)\ **Replies:** 1\ **Last updated:** [December 30, 2021, 7:44am UTC](https://forum.flow.com/t/timestamp-to-date/2662 "2021-12-30T07:44:16Z")
Hi, is there any function that can be used to convert the Flow timestamp to an actual date, like dd-mm-yyyy? --- ## [Transaction Error execution error code 1101: \[Error Code: 1101\] cadence runtime error Execution failed:](https://forum.flow.com/t/transaction-error-execution-error-code-1101-error-code-1101-cadence-runtime-error-execution-failed/2133)
**Author:** [@buzz](https://forum.flow.com/u/buzz)\ **Replies:** 2\ **Last updated:** [December 10, 2021, 9:36am UTC](https://forum.flow.com/t/transaction-error-execution-error-code-1101-error-code-1101-cadence-runtime-error-execution-failed/2133 "2021-12-10T09:36:46Z")
This is the transaction code which will be used to list item in market import PinataPartyContract from 0xf8d6e0586b0a20c7 import PinnieToken from 0xf8d6e0586b0a20c7 import MarketplaceContract from 0xf8d6e0586b0a20c7 tr… --- ## [New Cadence FLIP for restricting field mutation](https://forum.flow.com/t/new-cadence-flip-for-restricting-field-mutation/2571)
**Author:** [@sainati](https://forum.flow.com/u/sainati)\ **Replies:** 0\ **Last updated:** [November 29, 2021, 7:41pm UTC](https://forum.flow.com/t/new-cadence-flip-for-restricting-field-mutation/2571 "2021-11-29T19:41:02Z")
Hi Community, I have proposed a FLIP (https://github.com/onflow/flow/pull/703) that would address a common footgun developers run into when using Cadence: accidentally exposing state and fields from contracts or objects… --- ## [The emulator can run normally, but an error is reported in testnet](https://forum.flow.com/t/the-emulator-can-run-normally-but-an-error-is-reported-in-testnet/2548)
**Author:** [@ben1](https://forum.flow.com/u/ben1)\ **Replies:** 2\ **Last updated:** [November 24, 2021, 2:31am UTC](https://forum.flow.com/t/the-emulator-can-run-normally-but-an-error-is-reported-in-testnet/2548 "2021-11-24T02:31:19Z")
I have a piece of code that can run normally in the emulator, but an error is reported in testnet pub resource somename{ destroy () { emit completed( address: self.owner?.address! … --- ## [My transaction is never SEALED(on testnet)](https://forum.flow.com/t/my-transaction-is-never-sealed-on-testnet/2511)
**Author:** [@newbdez33](https://forum.flow.com/u/newbdez33)\ **Replies:** 0\ **Last updated:** [November 3, 2021, 5:19am UTC](https://forum.flow.com/t/my-transaction-is-never-sealed-on-testnet/2511 "2021-11-03T05:19:24Z")
What should I do? the transaction stuck on await executing. https://testnet.flowscan.org/transaction/a777fc8925d28fbac8cccbd40de7f7b7e98b1f9a7c9c6cbad85803ff98336fb3 --- ## ["raw private key is not valid"](https://forum.flow.com/t/raw-private-key-is-not-valid/1451)
**Author:** [@johnrobmiller](https://forum.flow.com/u/johnrobmiller)\ **Replies:** 1\ **Last updated:** [October 27, 2021, 9:19pm UTC](https://forum.flow.com/t/raw-private-key-is-not-valid/1451 "2021-10-27T21:19:09Z")
I’m learning about Cadence and block-chain technology, which is fun and new for me, but I keep on running into this error when trying to do things with the Flow emulator in the Flow-CLI. Here are a few of the commands I… --- ## [Get property from resource in collection](https://forum.flow.com/t/get-property-from-resource-in-collection/1846)
**Author:** [@kalitamih](https://forum.flow.com/u/kalitamih)\ **Replies:** 2\ **Last updated:** [October 23, 2021, 9:36pm UTC](https://forum.flow.com/t/get-property-from-resource-in-collection/1846 "2021-10-23T21:36:24Z")
Hi guys. I am learning cadence by tutorial. I have some misunderstanding in the 4th part (Non-Fungible Tokens). I want to add some extra information in NFT resource. I add some property “meta” in this resource and I cre… --- ## [Cannot deploy invalid contract](https://forum.flow.com/t/cannot-deploy-invalid-contract/2484)
**Author:** [@Sarath](https://forum.flow.com/u/Sarath)\ **Replies:** 1\ **Last updated:** [October 22, 2021, 11:44am UTC](https://forum.flow.com/t/cannot-deploy-invalid-contract/2484 "2021-10-22T11:44:09Z")
Hi, i try to deploy the bellow contract, but i am getting error transaction() { prepare(admin: AuthAccount) { let code: \[UInt8\] = “f845b8404d171ee5ee7303d91db44363d39230cef2ed8f6f48e15a10756458ffda0b6bddb232d05eb1b6a… --- ## [Error in Scope While Importing From Local File](https://forum.flow.com/t/error-in-scope-while-importing-from-local-file/1898)
**Author:** [@johnsmith1963](https://forum.flow.com/u/johnsmith1963)\ **Replies:** 3\ **Last updated:** [May 12, 2021, 1:14pm UTC](https://forum.flow.com/t/error-in-scope-while-importing-from-local-file/1898 "2021-05-12T13:14:34Z")
Hey all - me and my team are new to flow - and having a bit of trouble with creating our own smart contracts. We are trying to follow along with the developer tutorial - but we are current stuck when trying to import a … --- ## [In https://github.com/onflow/flow-nft/ can not get NFT metadata](https://forum.flow.com/t/in-https-github-com-onflow-flow-nft-can-not-get-nft-metadata/2455)
**Author:** [@qifufu](https://forum.flow.com/u/qifufu)\ **Replies:** 1\ **Last updated:** [October 12, 2021, 7:54pm UTC](https://forum.flow.com/t/in-https-github-com-onflow-flow-nft-can-not-get-nft-metadata/2455 "2021-10-12T19:54:35Z")
value of type &NonFungibleToken.NFT has no member metadata. unknown member I can’t cast NonFungibleToken.NFT as ExampleToken.NFT mismatched types. expected &ExampleNFT.NFT, got &NonFungibleToken.NFT --- ## [A VSCode extension migration to Vim/NeoVim](https://forum.flow.com/t/a-vscode-extension-migration-to-vim-neovim/2408)
**Author:** [@Lucklyric](https://forum.flow.com/u/Lucklyric)\ **Replies:** 2\ **Last updated:** [September 22, 2021, 6:32pm UTC](https://forum.flow.com/t/a-vscode-extension-migration-to-vim-neovim/2408 "2021-09-22T18:32:51Z")
Many members of our Dapp team are heavy Vim users, and we believe there will be a demand for vim support in the future, given the growing popularity of Flow and Cadence. We were starting to work on a vscode-cadence exten… --- ## [Casting Address field return nil](https://forum.flow.com/t/casting-address-field-return-nil/2375)
**Author:** [@saadtroon](https://forum.flow.com/u/saadtroon)\ **Replies:** 3\ **Last updated:** [September 14, 2021, 3:41pm UTC](https://forum.flow.com/t/casting-address-field-return-nil/2375 "2021-09-14T15:41:09Z")
I was trying to cast input in address field but it always return nil. Any help would be appreciated. transaction { prepare(acct: AuthAccount) {} execute { var someStruct: AnyStruct = 0x01 var address = someStruct a… --- ## [Contract storage layout](https://forum.flow.com/t/contract-storage-layout/2373)
**Author:** [@dryrunner](https://forum.flow.com/u/dryrunner)\ **Replies:** 2\ **Last updated:** [September 13, 2021, 8:52pm UTC](https://forum.flow.com/t/contract-storage-layout/2373 "2021-09-13T20:52:24Z")
For variables defined in the cadence contract, if they’re not explicitly save() to the storage path, where are they stored? For example the HelloWorld.cdc contract from the playground: access(all) contract HelloWorld { … --- ## [Is it possible to do an ecrecover() of an Ethereum address in a Cadence contract?](https://forum.flow.com/t/is-it-possible-to-do-an-ecrecover-of-an-ethereum-address-in-a-cadence-contract/684)
**Author:** [@dangerousfood](https://forum.flow.com/u/dangerousfood)\ **Replies:** 9\ **Last updated:** [September 10, 2021, 3:41pm UTC](https://forum.flow.com/t/is-it-possible-to-do-an-ecrecover-of-an-ethereum-address-in-a-cadence-contract/684 "2021-09-10T15:41:55Z")
Hi All, I am wanting to bind an Ethereum account using a resource. To do this I would like to sign some data using and Ethereum EOA. I then would like to validate the public key address that the data signed with the pr… --- ## [Cadence Contract Security Internal Review Checklist](https://forum.flow.com/t/cadence-contract-security-internal-review-checklist/2355)
**Author:** [@Ken](https://forum.flow.com/u/Ken)\ **Replies:** 0\ **Last updated:** [August 31, 2021, 4:01pm UTC](https://forum.flow.com/t/cadence-contract-security-internal-review-checklist/2355 "2021-08-31T16:01:49Z")
I started the internal security review checklist for Cadence. I would appreciate it greatly if you can take a look and give me some comments. Here is the link --- ## [Additional Abilities for Scripts](https://forum.flow.com/t/additional-abilities-for-scripts/677)
**Author:** [@dete](https://forum.flow.com/u/dete)\ **Replies:** 6\ **Last updated:** [August 31, 2021, 4:45am UTC](https://forum.flow.com/t/additional-abilities-for-scripts/677 "2021-08-31T04:45:29Z")
Right now, we more or less have two execution environments for Cadence (on the live network, not counting playground/emulator). We have the smart contract and transaction environment used to update the chain, and we have… --- ## [Encrypt data to anyone other than owner?](https://forum.flow.com/t/encrypt-data-to-anyone-other-than-owner/2322)
**Author:** [@Linenoise](https://forum.flow.com/u/Linenoise)\ **Replies:** 1\ **Last updated:** [August 25, 2021, 5:07pm UTC](https://forum.flow.com/t/encrypt-data-to-anyone-other-than-owner/2322 "2021-08-25T17:07:41Z")
New to flow and enjoying exploring the possibilities. Is there any way to store data in an NFT that can only be decrypted by the owner? Trying to avoid methods involving off block calls or required communication betwee… --- ## [How to get buyer address in a flow market purchase](https://forum.flow.com/t/how-to-get-buyer-address-in-a-flow-market-purchase/2167)
**Author:** [@quantum-guy7](https://forum.flow.com/u/quantum-guy7)\ **Replies:** 6\ **Last updated:** [August 25, 2021, 9:30am UTC](https://forum.flow.com/t/how-to-get-buyer-address-in-a-flow-market-purchase/2167 "2021-08-25T09:30:44Z")
Hi all. My question to you folks is: How do you determine the buyer (toAddress) when a moment is purchased?? I went through this contract link: https://flowscan.org/contract/A.c1e4f4f4c4257510.Market Any help is rea… --- ## [VIV3's Collectible NFTs ownership script](https://forum.flow.com/t/viv3s-collectible-nfts-ownership-script/2275)
**Author:** [@arthur\_spa](https://forum.flow.com/u/arthur_spa)\ **Replies:** 1\ **Last updated:** [August 18, 2021, 3:13pm UTC](https://forum.flow.com/t/viv3s-collectible-nfts-ownership-script/2275 "2021-08-18T15:13:02Z")
Hello everyone, I’m currently using the VIV3’s Collectible contract : https://flowscan.org/contract/A.37b92d1580b5c0b5.Collectible . I can now create Sets, Items and mint NFTs, but how can I see, with a script, which us… [Previous page](https://forum.flow.com/c/builders/37.md?page=2) [Next page](https://forum.flow.com/c/builders/37.md?page=4)