Coverage Report

Created: 2024-04-25 06:10

/src/uWebSockets/src/QueryParser.h
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/*
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 * Authored by Alex Hultman, 2018-2020.
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 * Intellectual property of third-party.
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *     http://www.apache.org/licenses/LICENSE-2.0
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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/* This module implements URI query parsing and retrieval of value given key */
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#ifndef UWS_QUERYPARSER_H
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#define UWS_QUERYPARSER_H
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#include <string_view>
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namespace uWS {
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    /* Takes raw query including initial '?' sign. Will inplace decode, so input will mutate */
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    static inline std::string_view getDecodedQueryValue(std::string_view key, std::string_view rawQuery) {
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        /* Can't have a value without a key */
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        if (!key.length()) {
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            return {};
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        }
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        /* Start with the whole querystring including initial '?' */
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        std::string_view queryString = rawQuery;
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        /* List of key, value could be cached for repeated fetches similar to how headers are, todo! */
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        while (queryString.length()) {
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            /* Find boundaries of this statement */
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            std::string_view statement = queryString.substr(1, queryString.find('&', 1) - 1);
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            /* Only bother if first char of key match (early exit) */
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            if (statement.length() && statement[0] == key[0]) {
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                /* Equal sign must be present and not in the end of statement */
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                auto equality = statement.find('=');
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                if (equality != std::string_view::npos) {
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                    std::string_view statementKey = statement.substr(0, equality);
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                    std::string_view statementValue = statement.substr(equality + 1);
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                    /* String comparison */
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                    if (key == statementKey) {
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                        /* Decode value inplace, put null at end if before length of original */
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                        char *in = (char *) statementValue.data();
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                        /* Write offset */
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                        unsigned int out = 0;
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                        /* Walk over all chars until end or null char, decoding in place */
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                        for (unsigned int i = 0; i < statementValue.length() && in[i]; i++) {
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                                /* Only bother with '%' */
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                                if (in[i] == '%') {
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                                    /* Do we have enough data for two bytes hex? */
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                                    if (i + 2 >= statementValue.length()) {
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                                        return {};
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                                    }
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                                    /* Two bytes hex */
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                                    int hex1 = in[i + 1] - '0';
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                                    if (hex1 > 9) {
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                                        hex1 &= 223;
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                                        hex1 -= 7;
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                                    }
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                                    int hex2 = in[i + 2] - '0';
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                                    if (hex2 > 9) {
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                                        hex2 &= 223;
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                                        hex2 -= 7;
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                                    }
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                                    *((unsigned char *) &in[out]) = (unsigned char) (hex1 * 16 + hex2);
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                                    i += 2;
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                                } else {
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                                    /* Is this even a rule? */
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                                    if (in[i] == '+') {
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                                        in[out] = ' ';
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                                    } else {
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                                        in[out] = in[i];
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                                    }
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                                }
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                                /* We always only write one char */
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                                out++;
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                        }
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                        /* If decoded string is shorter than original, put null char to stop next read */
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                        if (out < statementValue.length()) {
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                            in[out] = 0;
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                        }
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                        return statementValue.substr(0, out);
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                    }
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                } else {
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                    /* This querystring is invalid, cannot parse it */
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                    return {nullptr, 0};
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                }
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            }
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            queryString.remove_prefix(statement.length() + 1);
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        }
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        /* Nothing found is given as nullptr, while empty string is given as some pointer to the given buffer */
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        return {nullptr, 0};
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    }
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}
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#endif