refactor: increase string_view usage

diff --git a/src/blockfilter.cpp b/src/blockfilter.cpp
index 5e6702cc..94bcc497 100644
--- a/src/blockfilter.cpp
+++ b/src/blockfilter.cpp
@@ -4,6 +4,7 @@
 
 #include <mutex>
 #include <set>
+#include <string_view>
 
 #include <blockfilter.h>
 #include <crypto/siphash.h>
@@ -151,7 +152,8 @@ const std::string& BlockFilterTypeName(BlockFilterType filter_type)
     return it != g_filter_types.end() ? it->second : unknown_retval;
 }
 
-bool BlockFilterTypeByName(const std::string& name, BlockFilterType& filter_type) {
+bool BlockFilterTypeByName(std::string_view name, BlockFilterType& filter_type)
+{
     for (const auto& entry : g_filter_types) {
         if (entry.second == name) {
             filter_type = entry.first;
diff --git a/src/blockfilter.h b/src/blockfilter.h
index 8eab4afa..b70afb90 100644
--- a/src/blockfilter.h
+++ b/src/blockfilter.h
@@ -10,6 +10,7 @@
 #include <ios>
 #include <set>
 #include <string>
+#include <string_view>
 #include <unordered_set>
 #include <utility>
 #include <vector>
@@ -99,7 +100,7 @@ enum class BlockFilterType : uint8_t
 const std::string& BlockFilterTypeName(BlockFilterType filter_type);
 
 /** Find a filter type by its human-readable name. */
-bool BlockFilterTypeByName(const std::string& name, BlockFilterType& filter_type);
+bool BlockFilterTypeByName(std::string_view name, BlockFilterType& filter_type);
 
 /** Get a list of known filter types. */
 const std::set<BlockFilterType>& AllBlockFilterTypes();
diff --git a/src/common/messages.cpp b/src/common/messages.cpp
index fc0b4a88..e1169c76 100644
--- a/src/common/messages.cpp
+++ b/src/common/messages.cpp
@@ -16,6 +16,7 @@
 #include <cassert>
 #include <map>
 #include <string>
+#include <string_view>
 #include <utility>
 #include <vector>
 
@@ -91,7 +92,7 @@ std::string InvalidEstimateModeErrorMessage()
     return "Invalid estimate_mode parameter, must be one of: \"" + FeeModes("\", \"") + "\"";
 }
 
-bool FeeModeFromString(const std::string& mode_string, FeeEstimateMode& fee_estimate_mode)
+bool FeeModeFromString(std::string_view mode_string, FeeEstimateMode& fee_estimate_mode)
 {
     auto searchkey = ToUpper(mode_string);
     for (const auto& pair : FeeModeMap()) {
diff --git a/src/common/messages.h b/src/common/messages.h
index 5827fcce..5d33edac 100644
--- a/src/common/messages.h
+++ b/src/common/messages.h
@@ -12,6 +12,7 @@
 #define BITCOIN_COMMON_MESSAGES_H
 
 #include <string>
+#include <string_view>
 
 struct bilingual_str;
 
@@ -23,7 +24,7 @@ enum class TransactionError;
 
 namespace common {
 enum class PSBTError;
-bool FeeModeFromString(const std::string& mode_string, FeeEstimateMode& fee_estimate_mode);
+bool FeeModeFromString(std::string_view mode_string, FeeEstimateMode& fee_estimate_mode);
 std::string StringForFeeReason(FeeReason reason);
 std::string FeeModes(const std::string& delimiter);
 std::string FeeModeInfo(std::pair<std::string, FeeEstimateMode>& mode);
diff --git a/src/net.cpp b/src/net.cpp
index 066acc84..ef17824f 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -332,7 +332,7 @@ bool IsLocal(const CService& addr)
     return mapLocalHost.count(addr) > 0;
 }
 
-bool CConnman::AlreadyConnectedToHost(const std::string& host) const
+bool CConnman::AlreadyConnectedToHost(std::string_view host) const
 {
     LOCK(m_nodes_mutex);
     return std::ranges::any_of(m_nodes, [&host](CNode* node) { return node->m_addr_name == host; });
@@ -3626,7 +3626,7 @@ void CConnman::GetNodeStats(std::vector<CNodeStats>& vstats) const
     }
 }
 
-bool CConnman::DisconnectNode(const std::string& strNode)
+bool CConnman::DisconnectNode(std::string_view strNode)
 {
     LOCK(m_nodes_mutex);
     auto it = std::ranges::find_if(m_nodes, [&strNode](CNode* node) { return node->m_addr_name == strNode; });
diff --git a/src/net.h b/src/net.h
index 2b606cbe..6a591c4b 100644
--- a/src/net.h
+++ b/src/net.h
@@ -1246,7 +1246,7 @@ public:
     std::map<CNetAddr, LocalServiceInfo> getNetLocalAddresses() const;
     uint32_t GetMappedAS(const CNetAddr& addr) const;
     void GetNodeStats(std::vector<CNodeStats>& vstats) const;
-    bool DisconnectNode(const std::string& node);
+    bool DisconnectNode(std::string_view node);
     bool DisconnectNode(const CSubNet& subnet);
     bool DisconnectNode(const CNetAddr& addr);
     bool DisconnectNode(NodeId id);
@@ -1378,7 +1378,7 @@ private:
      * @param[in] host String of the form "host[:port]", e.g. "localhost" or "localhost:8333" or "1.2.3.4:8333".
      * @return true if connected to `host`.
      */
-    bool AlreadyConnectedToHost(const std::string& host) const;
+    bool AlreadyConnectedToHost(std::string_view host) const;
 
     /**
      * Determine whether we're already connected to a given address:port.
diff --git a/src/netaddress.cpp b/src/netaddress.cpp
index 7eb58f3e..fb2c2540 100644
--- a/src/netaddress.cpp
+++ b/src/netaddress.cpp
@@ -18,6 +18,7 @@
 #include <cstdint>
 #include <ios>
 #include <iterator>
+#include <string_view>
 #include <tuple>
 
 using util::ContainsNoNUL;
@@ -208,7 +209,7 @@ static void Checksum(std::span<const uint8_t> addr_pubkey, uint8_t (&checksum)[C
 
 }; // namespace torv3
 
-bool CNetAddr::SetSpecial(const std::string& addr)
+bool CNetAddr::SetSpecial(std::string_view addr)
 {
     if (!ContainsNoNUL(addr)) {
         return false;
@@ -225,16 +226,11 @@ bool CNetAddr::SetSpecial(const std::string& addr)
     return false;
 }
 
-bool CNetAddr::SetTor(const std::string& addr)
+bool CNetAddr::SetTor(std::string_view addr)
 {
-    static const char* suffix{".onion"};
-    static constexpr size_t suffix_len{6};
-
-    if (addr.size() <= suffix_len || addr.substr(addr.size() - suffix_len) != suffix) {
-        return false;
-    }
-
-    auto input = DecodeBase32(std::string_view{addr}.substr(0, addr.size() - suffix_len));
+    if (!addr.ends_with(".onion")) return false;
+    addr.remove_suffix(6);
+    auto input = DecodeBase32(addr);
 
     if (!input) {
         return false;
@@ -264,7 +260,7 @@ bool CNetAddr::SetTor(const std::string& addr)
     return false;
 }
 
-bool CNetAddr::SetI2P(const std::string& addr)
+bool CNetAddr::SetI2P(std::string_view addr)
 {
     // I2P addresses that we support consist of 52 base32 characters + ".b32.i2p".
     static constexpr size_t b32_len{52};
@@ -277,7 +273,7 @@ bool CNetAddr::SetI2P(const std::string& addr)
 
     // Remove the ".b32.i2p" suffix and pad to a multiple of 8 chars, so DecodeBase32()
     // can decode it.
-    const std::string b32_padded = addr.substr(0, b32_len) + "====";
+    const std::string b32_padded{tfm::format("%s====", addr.substr(0, b32_len))};
 
     auto address_bytes = DecodeBase32(b32_padded);
 
diff --git a/src/netaddress.h b/src/netaddress.h
index 7c311e2f..48dbf03a 100644
--- a/src/netaddress.h
+++ b/src/netaddress.h
@@ -18,6 +18,7 @@
 #include <cstdint>
 #include <ios>
 #include <string>
+#include <string_view>
 #include <vector>
 
 /**
@@ -151,7 +152,7 @@ public:
      * @returns Whether the operation was successful.
      * @see CNetAddr::IsTor(), CNetAddr::IsI2P()
      */
-    bool SetSpecial(const std::string& addr);
+    bool SetSpecial(std::string_view addr);
 
     bool IsBindAny() const; // INADDR_ANY equivalent
     [[nodiscard]] bool IsIPv4() const { return m_net == NET_IPV4; } // IPv4 mapped address (::FFFF:0:0/96, 0.0.0.0/0)
@@ -279,7 +280,7 @@ private:
      * @returns Whether the operation was successful.
      * @see CNetAddr::IsTor()
      */
-    bool SetTor(const std::string& addr);
+    bool SetTor(std::string_view addr);
 
     /**
      * Parse an I2P address and set this object to it.
@@ -288,7 +289,7 @@ private:
      * @returns Whether the operation was successful.
      * @see CNetAddr::IsI2P()
      */
-    bool SetI2P(const std::string& addr);
+    bool SetI2P(std::string_view addr);
 
     /**
      * Size of CNetAddr when serialized as ADDRv1 (pre-BIP155) (in bytes).
diff --git a/src/outputtype.cpp b/src/outputtype.cpp
index d4c2d95c..082641f5 100644
--- a/src/outputtype.cpp
+++ b/src/outputtype.cpp
@@ -20,7 +20,7 @@ static const std::string OUTPUT_TYPE_STRING_BECH32 = "bech32";
 static const std::string OUTPUT_TYPE_STRING_BECH32M = "bech32m";
 static const std::string OUTPUT_TYPE_STRING_UNKNOWN = "unknown";
 
-std::optional<OutputType> ParseOutputType(const std::string& type)
+std::optional<OutputType> ParseOutputType(std::string_view type)
 {
     if (type == OUTPUT_TYPE_STRING_LEGACY) {
         return OutputType::LEGACY;
diff --git a/src/outputtype.h b/src/outputtype.h
index 5a6f0539..4dde381b 100644
--- a/src/outputtype.h
+++ b/src/outputtype.h
@@ -12,6 +12,7 @@
 #include <array>
 #include <optional>
 #include <string>
+#include <string_view>
 #include <vector>
 
 enum class OutputType {
@@ -29,7 +30,7 @@ static constexpr auto OUTPUT_TYPES = std::array{
     OutputType::BECH32M,
 };
 
-std::optional<OutputType> ParseOutputType(const std::string& str);
+std::optional<OutputType> ParseOutputType(std::string_view str);
 const std::string& FormatOutputType(OutputType type);
 std::string FormatAllOutputTypes();