#pragma once #include #include #include #include namespace DB { /** * This class represents table engine for external urls. * It sends HTTP GET to server when select is called and * HTTP POST when insert is called. In POST request the data is send * using Chunked transfer encoding, so server have to support it. */ class IStorageURLBase : public IStorage { public: String getTableName() const override { return table_name; } BlockInputStreams read(const Names & column_names, const SelectQueryInfo & query_info, const Context & context, QueryProcessingStage::Enum processed_stage, size_t max_block_size, unsigned num_streams) override; BlockOutputStreamPtr write(const ASTPtr & query, const Settings & settings) override; void rename(const String & new_path_to_db, const String & new_database_name, const String & new_table_name) override; protected: IStorageURLBase(const Poco::URI & uri_, const Context & context_, const std::string & table_name_, const String & format_name_, const ColumnsDescription & columns_); Poco::URI uri; const Context & context_global; private: String format_name; String table_name; virtual std::string getReadMethod() const; virtual std::vector> getReadURIParams(const Names & column_names, const SelectQueryInfo & query_info, const Context & context, QueryProcessingStage::Enum & processed_stage, size_t max_block_size) const; virtual std::function getReadPOSTDataCallback(const Names & column_names, const SelectQueryInfo & query_info, const Context & context, QueryProcessingStage::Enum & processed_stage, size_t max_block_size) const; virtual Block getHeaderBlock(const Names & column_names) const = 0; }; class StorageURL : public ext::shared_ptr_helper, public IStorageURLBase { public: StorageURL(const Poco::URI & uri_, const std::string & table_name_, const String & format_name_, const ColumnsDescription & columns_, Context & context_) : IStorageURLBase(uri_, context_, table_name_, format_name_, columns_) { } String getName() const override { return "URL"; } Block getHeaderBlock(const Names & /*column_names*/) const override { return getSampleBlock(); } }; }