Support anonymous requests

Author: ggcr

src/s3cpp/auth.cpp

@@ -13,18 +13,27 @@
 
 template <typename T>
 void AWSSigV4Signer::sign(HttpRequestBase<T>& request) {
-    // Autorization
-    const std::string hash_algo = "AWS4-HMAC-SHA256";
+    // For anonymous requests (empty credentials), only add required headers but skip Authorization
+    const bool is_anonymous = access_key.empty() || secret_key.empty();
 
-    // Compute payload hash and set header ONLY for body requests
+    // Compute payload hash and set header for all requests
     std::string payload_hash;
     if constexpr (std::is_same_v<T, HttpBodyRequest>) {
         const std::string& body = static_cast<HttpBodyRequest&>(request).getBody();
         payload_hash = hex(sha256(body));
-        request.header("x-amz-content-sha256", payload_hash);
     } else {
+        // Empty payload hash for GET/HEAD requests
         payload_hash = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855";
     }
+    request.header("x-amz-content-sha256", payload_hash);
+
+    // Skip signing for anonymous requests
+    if (is_anonymous) {
+        return;
+    }
+
+    // Autorization
+    const std::string hash_algo = "AWS4-HMAC-SHA256";
 
     // Compute date and add it as a header
     const std::string timestamp = this->getTimestamp();

src/s3cpp/httpclient.cpp

@@ -74,7 +74,7 @@ std::expected<HttpResponse, std::string> HttpClient::execute_get(HttpRequest& re
     CURLcode code = curl_easy_perform(curl_handle);
     curl_slist_free_all(list);
     if (code != CURLE_OK) {
-        return std::unexpected<std::string>(std::format("libcurl error: {}", curl_easy_strerror(code)));
+        return std::unexpected<std::string>(std::format("libcurl error on execute_get: {}", curl_easy_strerror(code)));
     }
 
     // get HTTP code
@@ -115,7 +115,7 @@ std::expected<HttpResponse, std::string> HttpClient::execute_head(HttpRequest& r
     CURLcode code = curl_easy_perform(curl_handle);
     curl_slist_free_all(list);
     if (code != CURLE_OK) {
-        return std::unexpected<std::string>(std::format("libcurl error: {}", curl_easy_strerror(code)));
+        return std::unexpected<std::string>(std::format("libcurl error execute_head: {}", curl_easy_strerror(code)));
     }
 
     // get HTTP code
@@ -174,7 +174,7 @@ std::expected<HttpResponse, std::string> HttpClient::execute_post(HttpBodyReques
     CURLcode code = curl_easy_perform(curl_handle);
     curl_slist_free_all(list);
     if (code != CURLE_OK) {
-        return std::unexpected<std::string>(std::format("libcurl error: {}", curl_easy_strerror(code)));
+        return std::unexpected<std::string>(std::format("libcurl error execute_post: {}", curl_easy_strerror(code)));
     }
 
     // get HTTP code
@@ -229,7 +229,7 @@ std::expected<HttpResponse, std::string> HttpClient::execute_delete(HttpBodyRequ
     CURLcode code = curl_easy_perform(curl_handle);
     curl_slist_free_all(list);
     if (code != CURLE_OK) {
-        return std::unexpected<std::string>(std::format("libcurl error: {}", curl_easy_strerror(code)));
+        return std::unexpected<std::string>(std::format("libcurl error execute_delete: {}", curl_easy_strerror(code)));
     }
 
     // get HTTP code

src/s3cpp/s3.cpp

@@ -607,7 +607,7 @@ Error S3Client::deserializeError(const std::vector<XMLNode>& nodes) {
         } else if (node.tag == "Error.Resource") {
             error.Resource = std::move(node.value);
         } else if (node.tag == "Error.RequestId") {
-            error.RequestId = Parser.parseNumber<int>(std::move(node.value));
+            error.RequestId = std::move(node.value);
         } else {
             continue;
         }

src/s3cpp/xml.hpp

@@ -184,7 +184,7 @@ class XMLParser {
 
     template <typename T>
     T parseNumber(const std::string s) {
-        int code;
+        T code;
         std::from_chars_result result;
         int base = 10;
 
@@ -204,7 +204,7 @@ class XMLParser {
         }
 
         if (result.ec == std::errc {}) {
-            return static_cast<T>(code);
+            return code;
         }
         throw std::runtime_error(std::format("Unable to parse number from '{}'", s));
     }

test/aws_test.cpp

@@ -0,0 +1,10 @@
+#include "gtest/gtest.h"
+#include <s3cpp/s3.h>
+#include <string>
+
+TEST(AWS, AWSAnonymousCredsListBucket) {
+    S3Client client("", "");
+    std::expected<ListObjectsResult, Error> res = client.ListObjects("fast-ai-imageclas");
+    if (!res)
+        FAIL() << std::format("ListObjects request failed. Code={}, Message={}", res.error().Code, res.error().Message);
+}