110 lines
4.4 KiB
C++
110 lines
4.4 KiB
C++
/**
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*
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* FLuxParser.h: InfluxDB flux query result parser
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*
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* MIT License
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*
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* Copyright (c) 2020 InfluxData
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#ifndef _FLUX_PARSER_H_
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#define _FLUX_PARSER_H_
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#include <vector>
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#include "CsvReader.h"
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#include "FluxTypes.h"
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/**
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* FluxQueryResult represents result from InfluxDB flux query.
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* It parses stream from server, line by line, so it allows to read a huge responses.
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*
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* Browsing thought the result is done by repeatedly calling the next() method, until it returns false.
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* Unsuccesful reading is distinqushed by non empty value from getError().
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*
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* As a flux query result can contain several tables differing by grouping key, use hasTableChanged() to
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* know when there is a new table.
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*
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* Single values are returned using getValueByIndex() or getValueByName() methods.
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* All row values are retreived by getValues().
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*
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* Always call close() at the of reading.
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*
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* FluxQueryResult supports passing by value.
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*/
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class FluxQueryResult {
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public:
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// Constructor for reading result
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FluxQueryResult(CsvReader *reader);
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// Constructor for error result
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FluxQueryResult(const String &error);
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// Copy constructor
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FluxQueryResult(const FluxQueryResult &other);
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// Assignment operator
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FluxQueryResult &operator=(const FluxQueryResult &other);
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// Advances to next values row in the result set.
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// Returns true on successful reading new row, false means end of the result set
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// or an error. Call getError() and check non empty value
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bool next();
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// Returns index of the column, or -1 if not found
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int getColumnIndex(const String &columnName);
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// Returns a converted value by index, or nullptr in case of missing value or wrong index
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FluxValue getValueByIndex(int index);
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// Returns a result value by column name, or nullptr in case of missing value or wrong column name
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FluxValue getValueByName(const String &columnName);
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// Returns flux datatypes of all columns
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std::vector<String> getColumnsDatatype() { return _data->_columnDatatypes; }
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// Returns names of all columns
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std::vector<String> getColumnsName() { return _data->_columnNames; }
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// Returns all values from current row
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std::vector<FluxValue> getValues() { return _data->_columnValues; }
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// Returns true if new table was encountered
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bool hasTableChanged() const { return _data->_tableChanged; }
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// Returns current table position in the results set
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int getTablePosition() const { return _data->_tablePosition; }
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// Returns an error found during parsing if any, othewise empty string
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String getError() { return _data->_error; }
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// Releases all resources and closes server reponse. It must be always called at end of reading.
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void close();
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// Descructor
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~FluxQueryResult();
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protected:
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FluxBase *convertValue(String &value, String &dataType);
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static FluxDateTime *convertRfc3339(String &value, const char *type);
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void clearValues();
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void clearColumns();
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private:
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class Data {
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public:
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Data(CsvReader *reader);
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~Data();
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CsvReader *_reader;
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int _tablePosition = -1;
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bool _tableChanged = false;
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std::vector<String> _columnDatatypes;
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std::vector<String> _columnNames;
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std::vector<FluxValue> _columnValues;
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String _error;
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};
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std::shared_ptr<Data> _data;
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};
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#endif //#_FLUX_PARSER_H_
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