feat(btc_api): integrate into chain proofs

src/block/block_header.cairo

@@ -139,7 +139,7 @@ func fetch_block_header(block_height) -> felt* {
     let (raw_block_header) = alloc();
 
     %{
-        block_hex = BTC_API.get_bock_header_raw(ids.block_height)
+        block_hex = BTC_API.get_block_header_raw(ids.block_height)
         from_hex(block_hex, ids.raw_block_header)
     %}
 

src/chain_proof/main.cairo

@@ -36,19 +36,7 @@ func fetch_block(block_height) -> felt* {
     let (block_data) = alloc();
 
     %{
-        import urllib3
-        import json
-        http = urllib3.PoolManager()
-
-        url = 'https://blockstream.info/api/block-height/' + str(ids.block_height)
-        r = http.request('GET', url)
-        block_hash = str(r.data, 'utf-8')
-
-        url = f'https://blockstream.info/api/block/{ block_hash }/raw'
-        r = http.request('GET', url)
-
-        block_hex = r.data.hex()
-
+        block_hex = BTC_API.get_bock_raw(ids.block_height)
         from_hex(block_hex, ids.block_data)
     %}
 

src/headers_chain_proof/main.cairo

@@ -47,19 +47,7 @@ func fetch_block(block_height) -> felt* {
     let (block_data) = alloc();
 
     %{
-        import urllib3
-        import json
-        http = urllib3.PoolManager()
-
-        url = 'https://blockstream.info/api/block-height/' + str(ids.block_height)
-        r = http.request('GET', url)
-        block_hash = str(r.data, 'utf-8')
-
-        url = f'https://blockstream.info/api/block/{ block_hash }/raw'
-        r = http.request('GET', url)
-
-        block_hex = r.data.hex()
-
+        block_hex = BTC_API.get_block_header_raw(ids.block_height)
         from_hex(block_hex, ids.block_data)
     %}
 

src/transaction/transaction.cairo

@@ -220,7 +220,7 @@ func fetch_transaction(block_height, tx_index) -> felt* {
 
     %{
         # BTC_API is defined in src/utils/python_utils.cairo
-        tx_hex = BTC_API.get_transaction(ids.block_height, ids.tx_index)
+        tx_hex = BTC_API.get_transaction_raw(ids.block_height, ids.tx_index)
         from_hex(tx_hex, ids.raw_transaction)
     %}
     return raw_transaction;
@@ -337,7 +337,9 @@ func validate_output{range_check_ptr, utreexo_roots: felt*, hash_ptr: HashBuilti
 // See also:
 // - https://developer.bitcoin.org/devguide/transactions.html#signature-hash-types
 //
-func write_transaction{writer: Writer, range_check_ptr, bitwise_ptr: BitwiseBuiltin*}(transaction: Transaction) {
+func write_transaction{writer: Writer, range_check_ptr, bitwise_ptr: BitwiseBuiltin*}(
+    transaction: Transaction
+) {
     alloc_locals;
     write_uint32(transaction.version);
 

src/utils/btc_api.py

@@ -113,13 +113,16 @@ def get_transaction_raw(self, block_height, tx_index):
         return tx_hex
 
     # Expecting bitcoind client with -txindex
-    @lru_cache(maxsize=CACHE_SIZE_LARGE_DATA)
     def get_transaction(self, block_height, tx_index):
         block_hash = self.get_block_hash(block_height)
         tx_id = self.rpc.getblock(block_hash)['tx'][tx_index]
         tx_json = self.rpc.getrawtransaction(f'{tx_id}', True)
         return tx_json
 
+    def get_transaction_by_id(self, txid):
+        tx_json = self.rpc.getrawtransaction(f'{tx_id}', True)
+        return tx_json
+
 
 class EsplorerAPI(BTCAPI):
     def __init__(self, base_url):
@@ -203,30 +206,34 @@ def get_transaction_raw(self, block_height, tx_index):
                 r.data.decode('utf-8'))
             exit(-1)
         return tx_hex
-
+    
     @lru_cache(maxsize=CACHE_SIZE_LARGE_DATA)
-    def get_transaction(self, block_height, tx_index):
-        block_hash = self.get_block_hash(block_height)
-        url = self.base_url + f'block/{block_hash}/txid/' + str(tx_index)
+    def get_transaction_by_id(self, txid):
+        url = self.base_url + f'tx/{txid}'
         r = self.pool_manager.request('GET', url)
-        txid = r.data.decode('utf-8')
+        tx = json.loads(r.data)
         if r.status != 200:
             print(
-                f'ERROR: get_transaction({block_height}, {tx_index}) could not retrieve tx_id from the remote API: ',
+                f'ERROR: get_transaction_by_id({txid}) could not retrieve tx_id from the remote API: ',
                 r.status,
                 r.data.decode('utf-8'))
             exit(-1)
-        url = self.base_url + f'tx/{txid}'
+        return tx
+
+
+    @lru_cache(maxsize=CACHE_SIZE_LARGE_DATA)
+    def get_transaction(self, block_height, tx_index):
+        block_hash = self.get_block_hash(block_height)
+        url = self.base_url + f'block/{block_hash}/txid/' + str(tx_index)
         r = self.pool_manager.request('GET', url)
-        tx = json.loads(r.data)
+        txid = r.data.decode('utf-8')
         if r.status != 200:
             print(
                 f'ERROR: get_transaction({block_height}, {tx_index}) could not retrieve tx_id from the remote API: ',
                 r.status,
                 r.data.decode('utf-8'))
             exit(-1)
-        return tx
-
+        return self.get_transaction_by_id(txid)
 
 if __name__ == '__main__':
     API = BTCAPI.make_BTCAPI()

src/utils/python_utils.cairo

@@ -4,7 +4,8 @@ func setup_python_defs() {
         # Note: This import requires $PYTHONPATH to include the zerosync path.
         #       Currently appended in Makefile.
         from src.utils.btc_api import BTCAPI
-        global BTC_API = BTCAPI.makeBTCAPI()
+        global BTC_API
+        BTC_API = BTCAPI.make_BTCAPI()
         import re
         def hex_to_felt(hex_string):
             # Seperate hex_string into chunks of 8 chars.

src/utxo_set/utxo_set.cairo

@@ -40,17 +40,7 @@ func utxo_set_extract{hash_ptr: HashBuiltin*, utreexo_roots: felt*}(txid: felt*,
     setup_python_defs();
     %{
         txid = hash_from_memory(ids.txid) 
-
-        import urllib3
-        http = urllib3.PoolManager()
-        url = 'https://blockstream.info/api/tx/' + txid
-        r = http.request('GET', url)
-        if r.status != 200:
-            print("ERROR: Utxo_set_extract received a bad answer from the API: ", r.status, r.data.decode('utf-8'))
-            exit(-1)
-
-        import json
-        tx = json.loads(r.data)
+        tx = BTC_API.get_transaction_by_id(txid)
         tx_output = tx["vout"][ids.vout]
 
         ids.amount = tx_output["value"]