add scoped providers (#18)

.github/workflows/test.yml

@@ -24,6 +24,6 @@ jobs:
       with:
         node-version: '14'
     - name: Install Flow CLI
-      run: bash -ci "$(curl -fsSL https://raw.githubusercontent.com/onflow/flow-cli/master/install.sh)" -- v1.3.3
+      run: bash -ci "$(curl -fsSL https://raw.githubusercontent.com/onflow/flow-cli/master/install.sh)" -- v1.5.0
     - name: Run tests
       run: sh ./test.sh

README.md

@@ -57,6 +57,11 @@ Currently, the list includes:
 | TokenForwarding | 0x51ea0e37c27a1f1a | 0xe544175ee0461c4b |
 | DapperUtilityCoin | 0x82ec283f88a62e65 | 0xead892083b3e2c6c |
 | FlowUtilityToken | 0x82ec283f88a62e65 | 0xead892083b3e2c6c |
+| ArrayUtils| 0x31ad40c07a2a9788 | 0xa340dc0a4ec828ab |
+| StringUtils| 0x31ad40c07a2a9788 | 0xa340dc0a4ec828ab |
+| AddressUtils | 0x31ad40c07a2a9788 | 0xa340dc0a4ec828ab |
+| ScopedNFTProviders | 0x31ad40c07a2a9788 | 0xa340dc0a4ec828ab |
+| ScopedFTProviders | 0x31ad40c07a2a9788 | 0xa340dc0a4ec828ab |
 
 
 ## Using a contract

contracts/flow-utils/ScopedFTProviders.cdc

@@ -0,0 +1,120 @@
+import "FungibleToken"
+import "StringUtils"
+
+// ScopedFTProviders
+//
+// TO AVOID RISK, PLEASE DEPLOY YOUR OWN VERSION OF THIS CONTRACT SO THAT
+// MALICIOUS UPDATES ARE NOT POSSIBLE
+//
+// ScopedProviders are meant to solve the issue of unbounded access FungibleToken vaults
+// when a provider is called for.
+pub contract ScopedFTProviders {
+    pub struct interface FTFilter {
+        pub fun canWithdrawAmount(_ amount: UFix64): Bool
+        pub fun markAmountWithdrawn(_ amount: UFix64)
+        pub fun getDetails(): {String: AnyStruct}
+    }
+
+    pub struct AllowanceFilter: FTFilter {
+        access(self) let allowance: UFix64
+        access(self) var allowanceUsed: UFix64
+
+        init(_ allowance: UFix64) {
+            self.allowance = allowance
+            self.allowanceUsed = 0.0
+        }
+
+        pub fun canWithdrawAmount(_ amount: UFix64): Bool {
+            return amount + self.allowanceUsed <= self.allowance
+        }
+
+        pub fun markAmountWithdrawn(_ amount: UFix64) {
+            self.allowanceUsed = self.allowanceUsed + amount
+        }
+
+        pub fun getDetails(): {String: AnyStruct} {
+            return {
+                "allowance": self.allowance,
+                "allowanceUsed": self.allowanceUsed
+            }
+        }
+    }
+
+    // ScopedFTProvider
+    //
+    // A ScopedFTProvider is a wrapped FungibleTokenProvider with
+    // filters that can be defined by anyone using the ScopedFTProvider.
+    pub resource ScopedFTProvider: FungibleToken.Provider {
+        access(self) let provider: Capability<&{FungibleToken.Provider}>
+        access(self) var filters: [{FTFilter}]
+
+        // block timestamp that this provider can no longer be used after
+        access(self) let expiration: UFix64?
+
+        pub init(provider: Capability<&{FungibleToken.Provider}>, filters: [{FTFilter}], expiration: UFix64?) {
+            self.provider = provider
+            self.filters = filters
+            self.expiration = expiration
+        }
+
+        pub fun check(): Bool {
+            return self.provider.check()
+        }
+
+        pub fun isExpired(): Bool {
+            if let expiration = self.expiration {
+                return getCurrentBlock().timestamp >= expiration
+            }
+            return false
+        }
+
+        pub fun canWithdraw(_ amount: UFix64): Bool {
+            if self.isExpired() {
+                return false
+            }
+
+            for filter in self.filters {
+                if !filter.canWithdrawAmount(amount) {
+                    return false
+                }
+            }
+
+            return true
+        }
+
+        pub fun withdraw(amount: UFix64): @FungibleToken.Vault {
+            pre {
+                !self.isExpired(): "provider has expired"
+            }
+
+            var i = 0
+            while i < self.filters.length {
+                if !self.filters[i].canWithdrawAmount(amount) {
+                    panic(StringUtils.join(["cannot withdraw tokens. filter of type", self.filters[i].getType().identifier, "failed."], " "))
+                }
+
+                self.filters[i].markAmountWithdrawn(amount)
+                i = i + 1
+            }
+
+            return <-self.provider.borrow()!.withdraw(amount: amount)
+        }
+
+        pub fun getDetails(): [{String: AnyStruct}] {
+            let details: [{String: AnyStruct}] = []
+            for filter in self.filters {
+                details.append(filter.getDetails())
+            }
+
+            return details
+        }
+    }
+
+    pub fun createScopedFTProvider(
+        provider: Capability<&{FungibleToken.Provider}>,
+        filters: [{FTFilter}],
+        expiration: UFix64?
+    ): @ScopedFTProvider {
+        return <- create ScopedFTProvider(provider: provider, filters: filters, expiration: expiration)
+    }
+}

contracts/flow-utils/ScopedNFTProviders.cdc

@@ -0,0 +1,162 @@
+import "NonFungibleToken"
+import "StringUtils"
+
+// ScopedNFTProviders
+//
+// TO AVOID RISK, PLEASE DEPLOY YOUR OWN VERSION OF THIS CONTRACT SO THAT
+// MALICIOUS UPDATES ARE NOT POSSIBLE
+//
+// ScopedNFTProviders are meant to solve the issue of unbounded access to NFT Collections.
+// A provider can be given extensible filters which allow limited access to resources based on any trait on the NFT itself.
+//
+// By using a scoped provider, only a subset of assets can be taken if the provider leaks
+// instead of the entire nft collection.
+pub contract ScopedNFTProviders {
+    pub struct interface NFTFilter {
+        pub fun canWithdraw(_ nft: &NonFungibleToken.NFT): Bool
+        pub fun markWithdrawn(_ nft: &NonFungibleToken.NFT)
+        pub fun getDetails(): {String: AnyStruct}
+    }
+
+    pub struct NFTIDFilter: NFTFilter {
+        // the ids that are allowed to be withdrawn.
+        // If ids[num] is false, the id cannot be withdrawn anymore
+        access(self) let ids: {UInt64: Bool}
+
+        init(_ ids: [UInt64]) {
+            let d: {UInt64: Bool} = {}
+            for i in ids {
+                d[i] = true
+            }
+            self.ids = d
+        }
+
+        pub fun canWithdraw(_ nft: &NonFungibleToken.NFT): Bool {
+            return self.ids[nft.id] != nil && self.ids[nft.id] == true
+        }
+
+        pub fun markWithdrawn(_ nft: &NonFungibleToken.NFT) {
+            self.ids[nft.id] = false
+        }
+
+        pub fun getDetails(): {String: AnyStruct} {
+            return {
+                "ids": self.ids
+            }
+        }
+    }
+
+    pub struct UUIDFilter: NFTFilter {
+        // the ids that are allowed to be withdrawn.
+        // If ids[num] is false, the id cannot be withdrawn anymore
+        access(self) let uuids: {UInt64: Bool}
+
+        init(_ uuids: [UInt64]) {
+            let d: {UInt64: Bool} = {}
+            for i in uuids {
+                d[i] = true
+            }
+            self.uuids = d
+        }
+
+        pub fun canWithdraw(_ nft: &NonFungibleToken.NFT): Bool {
+            return self.uuids[nft.uuid] != nil && self.uuids[nft.uuid]! == true
+        }
+
+        pub fun markWithdrawn(_ nft: &NonFungibleToken.NFT) {
+            self.uuids[nft.uuid] = false
+        }
+
+        pub fun getDetails(): {String: AnyStruct} {
+            return {
+                "uuids": self.uuids
+            }
+        }
+    }
+
+    // ScopedNFTProvider
+    //
+    // Wrapper around an NFT Provider that is restricted to specific ids.
+    pub resource ScopedNFTProvider: NonFungibleToken.Provider {
+        access(self) let provider: Capability<&{NonFungibleToken.Provider, NonFungibleToken.CollectionPublic}>
+        access(self) let filters: [{NFTFilter}]
+
+        // block timestamp that this provider can no longer be used after
+        access(self) let expiration: UFix64?
+
+         pub fun isExpired(): Bool {
+            if let expiration = self.expiration {
+                return getCurrentBlock().timestamp >= expiration
+            }
+            return false
+        }
+
+        pub init(provider: Capability<&{NonFungibleToken.Provider, NonFungibleToken.CollectionPublic}>, filters: [{NFTFilter}], expiration: UFix64?) {
+            self.provider = provider
+            self.expiration = expiration
+            self.filters = filters
+        }
+
+        pub fun canWithdraw(_ id: UInt64): Bool {
+            if self.isExpired() {
+                return false
+            }
+
+            let nft = self.provider.borrow()!.borrowNFT(id: id)
+            if nft == nil {
+                return false
+            }
+
+            var i = 0
+            while i < self.filters.length {
+                if !self.filters[i].canWithdraw(nft) {
+                    return false
+                }
+                i = i + 1
+            }
+            return true
+        }
+
+        pub fun check(): Bool {
+            return self.provider.check()
+        }
+
+        pub fun withdraw(withdrawID: UInt64): @NonFungibleToken.NFT {
+            pre {
+                !self.isExpired(): "provider has expired"
+            }
+
+            let nft <- self.provider.borrow()!.withdraw(withdrawID: withdrawID)
+            let ref = &nft as &NonFungibleToken.NFT
+
+            var i = 0
+            while i < self.filters.length {
+                if !self.filters[i].canWithdraw(ref) {
+                    panic(StringUtils.join(["cannot withdraw nft. filter of type", self.filters[i].getType().identifier, "failed."], " "))
+                }
+
+                self.filters[i].markWithdrawn(ref)
+                i = i + 1
+            }
+
+            return <-nft
+        }
+
+        pub fun getDetails(): [{String: AnyStruct}] {
+            let details: [{String: AnyStruct}] = []
+            for f in self.filters {
+                details.append(f.getDetails())
+            }
+
+            return details
+        }
+    }
+
+    pub fun createScopedNFTProvider(
+        provider: Capability<&{NonFungibleToken.Provider, NonFungibleToken.CollectionPublic}>,
+        filters: [{NFTFilter}],
+        expiration: UFix64?
+    ): @ScopedNFTProvider {
+        return <- create ScopedNFTProvider(provider: provider, filters: filters, expiration: expiration)
+    }
+}

example/contracts/Importer.cdc

@@ -10,6 +10,8 @@ import "LostAndFoundHelper"
 import "DapperOffersV2"
 import "TopShot"
 import "AddressUtils"
+import "ScopedNFTProviders"
+import "ScopedFTProviders"
 
 // This contract doesn't do anything, it's just to show that deployments work
 // with this import system

flow.json

@@ -291,6 +291,22 @@
         "testnet": "0x31ad40c07a2a9788",
         "mainnet": "0xa340dc0a4ec828ab"
       }
+    },
+    "ScopedFTProviders": {
+      "source": "./contracts/flow-utils/ScopedFTProviders.cdc",
+      "aliases": {
+        "emulator": "0xf8d6e0586b0a20c7",
+        "testnet": "0x31ad40c07a2a9788",
+        "mainnet": "0xa340dc0a4ec828ab"
+      }
+    },
+    "ScopedNFTProviders": {
+      "source": "./contracts/flow-utils/ScopedNFTProviders.cdc",
+      "aliases": {
+        "emulator": "0xf8d6e0586b0a20c7",
+        "testnet": "0x31ad40c07a2a9788",
+        "mainnet": "0xa340dc0a4ec828ab"
+      }
     }
   },
   "deployments": {
@@ -315,7 +331,9 @@
         "TopShotLocking",
         "ArrayUtils",
         "StringUtils",
-        "AddressUtils"
+        "AddressUtils",
+        "ScopedNFTProviders",
+        "ScopedFTProviders"
       ],
       "emulator-ft": [
         "FungibleToken",

package.json

@@ -1,6 +1,6 @@
 {
     "name": "@flowtyio/flow-contracts",
-    "version": "0.0.16",
+    "version": "0.0.17",
     "main": "index.json",
     "description": "An NPM package for common flow contracts",
     "author": "flowtyio",