From c0ce0fb9a8a600596eb75fe01c1b41152c9e3770 Mon Sep 17 00:00:00 2001
From: Krzysztof Kaczor <krzkaczor@gmail.com>
Date: Tue, 30 Sep 2025 09:21:19 +0200
Subject: [PATCH 1/2] Fix etherscan urls

---
 packages/ethereum-viewer/src/explorer/fetchFiles.test.ts | 2 +-
 packages/ethereum-viewer/src/explorer/fetchFiles.ts      | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/ethereum-viewer/src/explorer/fetchFiles.test.ts b/packages/ethereum-viewer/src/explorer/fetchFiles.test.ts
index 950c572..d8bb6b7 100644
--- a/packages/ethereum-viewer/src/explorer/fetchFiles.test.ts
+++ b/packages/ethereum-viewer/src/explorer/fetchFiles.test.ts
@@ -36,7 +36,7 @@ describe(fetchFiles.name, () => {
     await fetchFiles("optimistic.etherscan", "0x0", { fetch: f });
 
     const expectedPrefix =
-      "https://api-optimistic.etherscan.io/api?module=contract&action=getsourcecode&address=0x0&apikey=";
+      "https://api-optimistic.etherscan.io/api?&module=contract&action=getsourcecode&address=0x0&apikey=";
 
     assert(
       url?.startsWith(expectedPrefix),
diff --git a/packages/ethereum-viewer/src/explorer/fetchFiles.ts b/packages/ethereum-viewer/src/explorer/fetchFiles.ts
index cc27921..fe1d462 100644
--- a/packages/ethereum-viewer/src/explorer/fetchFiles.ts
+++ b/packages/ethereum-viewer/src/explorer/fetchFiles.ts
@@ -44,7 +44,7 @@ export async function fetchFiles(
   const apiUrl = explorerApiUrls[apiName];
   const url =
     apiUrl +
-    "?module=contract" +
+    "&module=contract" +
     "&action=getsourcecode" +
     `&address=${contractAddress}` +
     `&apikey=${explorerApiKeys[apiName]}`;

From de8e905944bcb681bb1dc687c84929666d9ef5a8 Mon Sep 17 00:00:00 2001
From: Krzysztof Kaczor <krzkaczor@gmail.com>
Date: Tue, 30 Sep 2025 09:24:42 +0200
Subject: [PATCH 2/2] Fix

---
 .../src/explorer/fetchFiles.test.ts           |  2 +-
 .../src/explorer/fetchFiles.ts                | 22 ++++++++++++++-----
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/packages/ethereum-viewer/src/explorer/fetchFiles.test.ts b/packages/ethereum-viewer/src/explorer/fetchFiles.test.ts
index d8bb6b7..950c572 100644
--- a/packages/ethereum-viewer/src/explorer/fetchFiles.test.ts
+++ b/packages/ethereum-viewer/src/explorer/fetchFiles.test.ts
@@ -36,7 +36,7 @@ describe(fetchFiles.name, () => {
     await fetchFiles("optimistic.etherscan", "0x0", { fetch: f });
 
     const expectedPrefix =
-      "https://api-optimistic.etherscan.io/api?&module=contract&action=getsourcecode&address=0x0&apikey=";
+      "https://api-optimistic.etherscan.io/api?module=contract&action=getsourcecode&address=0x0&apikey=";
 
     assert(
       url?.startsWith(expectedPrefix),
diff --git a/packages/ethereum-viewer/src/explorer/fetchFiles.ts b/packages/ethereum-viewer/src/explorer/fetchFiles.ts
index fe1d462..ed12e82 100644
--- a/packages/ethereum-viewer/src/explorer/fetchFiles.ts
+++ b/packages/ethereum-viewer/src/explorer/fetchFiles.ts
@@ -42,12 +42,22 @@ export async function fetchFiles(
   }: FetchFilesOptions = {}
 ): Promise<FetchFilesResult> {
   const apiUrl = explorerApiUrls[apiName];
-  const url =
-    apiUrl +
-    "&module=contract" +
-    "&action=getsourcecode" +
-    `&address=${contractAddress}` +
-    `&apikey=${explorerApiKeys[apiName]}`;
+  let url;
+  if (apiUrl.includes("chainid=")) {
+    url =
+      apiUrl +
+      "&module=contract" +
+      "&action=getsourcecode" +
+      `&address=${contractAddress}` +
+      `&apikey=${explorerApiKeys[apiName]}`;
+  } else {
+    url =
+      apiUrl +
+      "?module=contract" +
+      "&action=getsourcecode" +
+      `&address=${contractAddress}` +
+      `&apikey=${explorerApiKeys[apiName]}`;
+  }
 
   const response = (await fetch(url)) as types.ContractSourceResponse;