[VC Issuance] Use persistent storage for VCs and Revocations (#181)

* Update vc_issuance_contract

* Update Readme

* Update CI to coverage

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
           version: 0.22.0
           # Due to a bug with cargo-tarpaulin crate with multi-line chain calls, the test coverage was reduced.
           # https://github.com/xd009642/tarpaulin/issues/949
-          args: --all-features --fail-under 98.0 --out Lcov
+          args: --all-features --fail-under 97.8 --out Lcov
       - name: Upload to Coveralls
         uses: coverallsapp/github-action@master
         with:

vc_issuance_contract/README.md

@@ -152,6 +152,7 @@ A contract error will be triggered if:
 
 - Invoker is not the contract admin.
 - Verifiable credential is not registered.
+- Verifiable credential is already revoked.
 
 ```rust
 fn revoke(e: Env, admin: Address, vc_id: String, date: String);
@@ -179,8 +180,9 @@ soroban contract invoke \
 | 1    | `AlreadyInitialized`    | Contract has already been initialized                                   |
 | 2    | `NotAuthorized`         | Invoker is not the contract admin                                       |
 | 3    | `AmountLimitExceeded`   | Provided amount exceeds the maximum allowed                             |
-| 4    | `VCNotFound`            | Verifiable credential not found                                          |
-| 5    | `IssuanceLimitExceeded` | Contract issuance limit exceeded                                        |
+| 4    | `VCNotFound`            | Verifiable credential not found                                         |
+| 5    | `VCAlreadyRevoked`      | Verifiable credential already revoked                                   |
+| 6    | `IssuanceLimitExceeded` | Contract issuance limit exceeded                                        |
 
 ## Development
 

vc_issuance_contract/src/contract.rs

@@ -1,17 +1,12 @@
-use crate::error::ContractError;
-use crate::revocation::Revocation;
 use crate::storage;
 use crate::vc_issuance_trait::VCIssuanceTrait;
 use crate::verifiable_credential;
+use crate::{error::ContractError, revocation};
 use soroban_sdk::{
     contract, contractimpl, contractmeta, map, panic_with_error, vec, Address, Env, FromVal, Map,
     String, Symbol, Val, Vec,
 };
 
-// MAXIMUM ENTRY TTL:
-// 31 days, 12 ledger close per minute.
-// (12 * 60 * 24 * 31) - 1
-const LEDGERS_TO_EXTEND: u32 = 535_679;
 const DEFAULT_AMOUNT: u32 = 20;
 const MAX_AMOUNT: u32 = 100;
 
@@ -41,9 +36,8 @@ impl VCIssuanceTrait for VCIssuanceContract {
         storage::write_vcs(&e, &Vec::new(&e));
         storage::write_vcs_revocations(&e, &Map::new(&e));
 
-        e.storage()
-            .instance()
-            .extend_ttl(LEDGERS_TO_EXTEND, LEDGERS_TO_EXTEND);
+        storage::extend_ttl_to_instance(&e);
+        storage::extend_ttl_to_persistent(&e);
     }
     fn issue(e: Env, admin: Address, vc_data: String, vault_contract: Address) -> String {
         validate_admin(&e, &admin);
@@ -91,11 +85,7 @@ impl VCIssuanceTrait for VCIssuanceContract {
         validate_admin(&e, &admin);
         validate_vc(&e, &vc_id);
 
-        let mut revocations = storage::read_vcs_revocations(&e);
-
-        revocations.set(vc_id.clone(), Revocation { vc_id, date });
-
-        storage::write_vcs_revocations(&e, &revocations);
+        revocation::revoke_vc(&e, vc_id, date);
     }
 }
 

vc_issuance_contract/src/error.rs

@@ -8,5 +8,6 @@ pub enum ContractError {
     NotAuthorized = 2,
     AmountLimitExceeded = 3,
     VCNotFound = 4,
-    IssuanceLimitExceeded = 5,
+    VCAlreadyRevoked = 5,
+    IssuanceLimitExceeded = 6,
 }

vc_issuance_contract/src/revocation.rs

@@ -1,8 +1,20 @@
-use soroban_sdk::{contracttype, String};
+use crate::error::ContractError;
+use crate::storage;
+use soroban_sdk::{contracttype, panic_with_error, Env, String};
 
 #[contracttype]
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct Revocation {
     pub vc_id: String,
     pub date: String,
 }
+
+pub fn revoke_vc(e: &Env, vc_id: String, date: String) {
+    let mut revocations = storage::read_vcs_revocations(e);
+
+    if revocations.contains_key(vc_id.clone()) {
+        panic_with_error!(e, ContractError::VCAlreadyRevoked)
+    }
+    revocations.set(vc_id.clone(), Revocation { vc_id, date });
+    storage::write_vcs_revocations(e, &revocations);
+}

vc_issuance_contract/src/storage.rs

@@ -1,14 +1,19 @@
 use crate::revocation::Revocation;
 use soroban_sdk::{contracttype, Address, Env, Map, String, Vec};
 
+// MAXIMUM ENTRY TTL:
+// 31 days, 12 ledger close per minute.
+// (12 * 60 * 24 * 31) - 1
+const LEDGERS_TO_EXTEND: u32 = 535_679;
+
 #[derive(Clone)]
 #[contracttype]
 pub enum DataKey {
-    Admin,                 // Address
-    IssuerDID,             // String
-    Amount,                // U32
-    VerifiableCredentials, // Vec<String>
-    RevocationList,        // Map<String, Revocation>
+    Admin,       // Address
+    IssuerDID,   // String
+    Amount,      // U32
+    VCs,         // Vec<String>
+    Revocations, // Map<String, Revocation>
 }
 
 pub fn has_admin(e: &Env) -> bool {
@@ -47,21 +52,39 @@ pub fn write_amount(e: &Env, amount: &u32) {
 }
 
 pub fn write_vcs(e: &Env, vc: &Vec<String>) {
-    let key = DataKey::VerifiableCredentials;
-    e.storage().instance().set(&key, vc)
+    let key = DataKey::VCs;
+    e.storage().persistent().set(&key, vc)
 }
 
 pub fn read_vcs(e: &Env) -> Vec<String> {
-    let key = DataKey::VerifiableCredentials;
-    e.storage().instance().get(&key).unwrap()
+    let key = DataKey::VCs;
+    e.storage().persistent().get(&key).unwrap()
 }
 
 pub fn write_vcs_revocations(e: &Env, revocations: &Map<String, Revocation>) {
-    let key = DataKey::RevocationList;
-    e.storage().instance().set(&key, revocations)
+    let key = DataKey::Revocations;
+    e.storage().persistent().set(&key, revocations)
 }
 
 pub fn read_vcs_revocations(e: &Env) -> Map<String, Revocation> {
-    let key = DataKey::RevocationList;
-    e.storage().instance().get(&key).unwrap()
+    let key = DataKey::Revocations;
+    e.storage().persistent().get(&key).unwrap()
+}
+
+pub fn extend_ttl_to_instance(e: &Env) {
+    e.storage()
+        .instance()
+        .extend_ttl(LEDGERS_TO_EXTEND, LEDGERS_TO_EXTEND);
+}
+
+pub fn extend_ttl_to_persistent(e: &Env) {
+    let vcs_key = DataKey::VCs;
+    let revocations_key = DataKey::Revocations;
+
+    e.storage()
+        .persistent()
+        .extend_ttl(&vcs_key, LEDGERS_TO_EXTEND, LEDGERS_TO_EXTEND);
+    e.storage()
+        .persistent()
+        .extend_ttl(&revocations_key, LEDGERS_TO_EXTEND, LEDGERS_TO_EXTEND);
 }

vc_issuance_contract/src/test/contract.rs

@@ -94,7 +94,7 @@ fn test_issue_with_invalid_admin() {
 }
 
 #[test]
-#[should_panic(expected = "HostError: Error(Contract, #5)")]
+#[should_panic(expected = "HostError: Error(Contract, #6)")]
 fn test_issue_when_amount_is_exceeded() {
     let VCIssuanceContractTest {
         env,
@@ -109,6 +109,24 @@ fn test_issue_when_amount_is_exceeded() {
     contract.issue(&admin, &vc_data, &vault_contract_id);
 }
 
+#[test]
+fn test_revoke_vc() {
+    let VCIssuanceContractTest {
+        env,
+        admin,
+        amount: _,
+        vc_data,
+        issuer_did,
+        contract,
+    } = VCIssuanceContractTest::setup();
+    let vault_contract_id = create_vc(&env, &admin, &contract, &issuer_did, &None);
+    let vc_id = contract.issue(&admin, &vc_data, &vault_contract_id);
+
+    let date = String::from_str(&env, "2023-12-05T21:37:44.389Z");
+
+    contract.revoke(&admin, &vc_id, &date);
+}
+
 #[test]
 #[should_panic(expected = "HostError: Error(Contract, #4)")]
 fn test_revoke_vc_with_invalid_vc() {
@@ -129,7 +147,8 @@ fn test_revoke_vc_with_invalid_vc() {
 }
 
 #[test]
-fn test_revoke_vc() {
+#[should_panic(expected = "HostError: Error(Contract, #5)")]
+fn test_revoke_vc_when_it_was_already_revoked() {
     let VCIssuanceContractTest {
         env,
         admin,
@@ -141,9 +160,11 @@ fn test_revoke_vc() {
     let vault_contract_id = create_vc(&env, &admin, &contract, &issuer_did, &None);
     let vc_id = contract.issue(&admin, &vc_data, &vault_contract_id);
 
-    let date = String::from_str(&env, "2023-12-05T21:37:44.389Z");
+    let date_1 = String::from_str(&env, "2023-12-05T21:37:44.389Z");
+    let date_2 = String::from_str(&env, "2023-21-05T21:37:44.389Z");
 
-    contract.revoke(&admin, &vc_id, &date);
+    contract.revoke(&admin, &vc_id, &date_1);
+    contract.revoke(&admin, &vc_id, &date_2);
 }
 
 #[test]