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1911db8c6d
This is a helper struct to parse HTTP messages from data in buffers from sockets. HTTP messages begin with headers which are CRLF-terminated lines (\n or \r\n) followed by an arbitrary amount of body data. Whitespace is trimmed from the field lines but not the body. https://httpwg.org/specs/rfc9110.html#rfc.section.5
71 lines
2.5 KiB
C++
71 lines
2.5 KiB
C++
// Copyright (c) 2019-present The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#include <util/string.h>
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#include <regex>
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#include <string>
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namespace util {
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void ReplaceAll(std::string& in_out, const std::string& search, const std::string& substitute)
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{
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if (search.empty()) return;
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in_out = std::regex_replace(in_out, std::regex(search), substitute);
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}
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LineReader::LineReader(std::span<const std::byte> buffer, size_t max_line_length)
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: start(buffer.begin()), end(buffer.end()), max_line_length(max_line_length), it(buffer.begin()) {}
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std::optional<std::string> LineReader::ReadLine()
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{
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if (it == end) {
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return std::nullopt;
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}
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auto line_start = it;
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size_t count = 0;
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while (it != end) {
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// Read a character from the incoming buffer and increment the iterator
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auto c = static_cast<char>(*it);
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++it;
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++count;
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// If the character we just consumed was \n, the line is terminated.
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// The \n itself does not count against max_line_length.
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if (c == '\n') {
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const std::string_view untrimmed_line(reinterpret_cast<const char*>(std::to_address(line_start)), count);
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const std::string_view line = TrimStringView(untrimmed_line); // delete leading and trailing whitespace including \r and \n
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return std::string(line);
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}
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// If the character we just consumed gives us a line length greater
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// than max_line_length, and we are not at the end of the line (or buffer) yet,
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// that means the line we are currently reading is too long, and we throw.
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if (count > max_line_length) {
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// Reset iterator
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it = line_start;
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throw std::runtime_error("max_line_length exceeded by LineReader");
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}
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}
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// End of buffer reached without finding a \n or exceeding max_line_length.
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// Reset the iterator so the rest of the buffer can be read granularly
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// with ReadLength() and return null to indicate a line was not found.
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it = line_start;
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return std::nullopt;
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}
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// Ignores max_line_length but won't overflow
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std::string LineReader::ReadLength(size_t len)
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{
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if (len == 0) return "";
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if (Remaining() < len) throw std::runtime_error("Not enough data in buffer");
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std::string out(reinterpret_cast<const char*>(std::to_address(it)), len);
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it += len;
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return out;
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}
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size_t LineReader::Remaining() const
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{
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return std::distance(it, end);
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}
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} // namespace util
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