String-escaping functions

Classes
class	pqxx::binarystring
	Binary data corresponding to PostgreSQL's "BYTEA" binary-string type. More...

Functions
std::string	pqxx::connection::esc (char const text[], std::size_t maxlen) const
	Escape string for use as SQL string literal on this connection. More...
std::string	pqxx::connection::esc (char const text[]) const
	Escape string for use as SQL string literal on this connection. More...
std::string	pqxx::connection::esc (std::string_view text) const
	Escape string for use as SQL string literal on this connection. More...
std::string	pqxx::connection::esc_raw (unsigned char const bin[], std::size_t len) const
	Escape binary string for use as SQL string literal on this connection. More...
std::string	pqxx::connection::unesc_raw (std::string const &text) const
	Unescape binary data, e.g. from a table field or notification payload. More...
std::string	pqxx::connection::unesc_raw (zview text) const
	Unescape binary data, e.g. from a table field or notification payload. More...
std::string	pqxx::connection::unesc_raw (char const text[]) const
	Unescape binary data, e.g. from a table field or notification payload. More...
std::string	pqxx::connection::quote_raw (unsigned char const bin[], std::size_t len) const
	Escape and quote a string of binary data. More...
std::string	pqxx::connection::quote_name (std::string_view identifier) const
	Escape and quote an SQL identifier for use in a query. More...
template<typename T >
std::string	pqxx::connection::quote (T const &t) const
	Represent object as SQL string, including quoting & escaping. More...
std::string	pqxx::connection::quote (binarystring const &) const
std::string	pqxx::connection::esc_like (std::string_view text, char escape_char='\\') const
	Escape string for literal LIKE match. More...
std::string	pqxx::transaction_base::esc (char const text[]) const
	Escape string for use as SQL string literal in this transaction. More...
std::string	pqxx::transaction_base::esc (char const text[], std::size_t maxlen) const
	Escape string for use as SQL string literal in this transaction. More...
std::string	pqxx::transaction_base::esc (std::string const &text) const
	Escape string for use as SQL string literal in this transaction. More...
std::string	pqxx::transaction_base::esc (std::string_view text) const
	Escape string for use as SQL string literal in this transaction. More...
std::string	pqxx::transaction_base::esc_raw (unsigned char const data[], std::size_t len) const
	Escape binary data for use as SQL string literal in this transaction. More...
std::string	pqxx::transaction_base::esc_raw (std::string const &) const
	Escape binary data for use as SQL string literal in this transaction. More...
std::string	pqxx::transaction_base::unesc_raw (std::string const &text) const
	Unescape binary data, e.g. from a table field or notification payload. More...
std::string	pqxx::transaction_base::unesc_raw (char const *text) const
	Unescape binary data, e.g. from a table field or notification payload. More...
template<typename T >
std::string	pqxx::transaction_base::quote (T const &t) const
	Represent object as SQL string, including quoting & escaping. More...
std::string	pqxx::transaction_base::quote_raw (unsigned char const bin[], std::size_t len) const
	Binary-escape and quote a binarystring for use as an SQL constant. More...
std::string	pqxx::transaction_base::quote_raw (std::string const &bin) const
std::string	pqxx::transaction_base::quote_name (std::string_view identifier) const
	Escape an SQL identifier for use in a query. More...
std::string	pqxx::transaction_base::esc_like (std::string const &bin, char escape_char='\\') const
	Escape string for literal LIKE match. More...

Detailed Description

Function Documentation

esc() [1/7]

std::string pqxx::transaction_base::esc

(

char const

text[]

)

const

Escape string for use as SQL string literal in this transaction.

esc() [2/7]

std::string pqxx::transaction_base::esc	(	char const	text[],
		std::size_t	maxlen
	)		const

Escape string for use as SQL string literal in this transaction.

esc() [3/7]

std::string pqxx::transaction_base::esc

(

std::string const &

text

)

const

Escape string for use as SQL string literal in this transaction.

esc() [4/7]

std::string pqxx::transaction_base::esc

(

std::string_view

text

)

const

Escape string for use as SQL string literal in this transaction.

esc() [5/7]

std::string pqxx::connection::esc	(	char const	text[],
		std::size_t	maxlen
	)		const

Escape string for use as SQL string literal on this connection.

Warning

This accepts a length, and it does not require a terminating zero byte. But if there is a zero byte, escaping stops there even if it's not at the end of the string!

esc() [6/7]

std::string pqxx::connection::esc

(

char const

text[]

)

const

Escape string for use as SQL string literal on this connection.

esc() [7/7]

std::string pqxx::connection::esc

(

std::string_view

text

)

const

Escape string for use as SQL string literal on this connection.

Warning

If the string contains a zero byte, escaping stops there even if it's not at the end of the string!

esc_like() [1/2]

std::string pqxx::transaction_base::esc_like	(	std::string const &	bin,
		char	escape_char = '\\'
	)		const

Escape string for literal LIKE match.

esc_like() [2/2]

std::string pqxx::connection::esc_like	(	std::string_view	text,
		char	escape_char = '\\'
	)		const

Escape string for literal LIKE match.

Use this when part of an SQL "LIKE" pattern should match only as a literal string, not as a pattern, even if it contains "%" or "_" characters that would normally act as wildcards.

The string does not get string-escaped or quoted. You do that later.

For instance, let's say you have a string name entered by the user, and you're searching a file column for items that match name followed by a dot and three letters. Even if name contains wildcard characters "%" or "_", you only want those to match literally, so "_" only matches "_" and "%" only matches a single "%".

You do that by "like-escaping" name, appending the wildcard pattern ".___", and finally, escaping and quoting the result for inclusion in your query:

tx.exec( "SELECT file FROM item WHERE file LIKE " + tx.quote(tx.esc_like(name) + ".___"));

The SQL "LIKE" operator also lets you choose your own escape character. This is supported, but must be a single-byte character.

References pqxx::check_cast(), pqxx::internal::enc_group(), and pqxx::connection::encoding_id().

esc_raw() [1/3]

std::string pqxx::transaction_base::esc_raw	(	unsigned char const	data[],
		std::size_t	len
	)		const

Escape binary data for use as SQL string literal in this transaction.

Raw, binary data is treated differently from regular strings. Binary strings are never interpreted as text, so they may safely include byte values or byte sequences that don't happen to represent valid characters in the character encoding being used.

The binary string does not stop at the first zero byte, as is the case with textual strings. Instead, they may contain zero bytes anywhere. If it happens to contain bytes that look like quote characters, or other things that can disrupt their use in SQL queries, they will be replaced with special escape sequences.

esc_raw() [2/3]

std::string pqxx::transaction_base::esc_raw

(

std::string const &

bin

)

const

Escape binary data for use as SQL string literal in this transaction.

References pqxx::transaction_base::conn(), and pqxx::connection::esc_raw().

esc_raw() [3/3]

std::string pqxx::connection::esc_raw	(	unsigned char const	bin[],
		std::size_t	len
	)		const

Escape binary string for use as SQL string literal on this connection.

Referenced by pqxx::transaction_base::esc_raw(), and pqxx::connection::quote_raw().

quote() [1/3]

template<typename T >

std::string pqxx::transaction_base::quote

(

T const &

t

)

const

Represent object as SQL string, including quoting & escaping.

Nulls are recognized and represented as SQL nulls.

quote() [2/3]

template<typename T >

std::string pqxx::connection::quote

(

T const &

t

)

const

Represent object as SQL string, including quoting & escaping.

Nulls are recognized and represented as SQL nulls. They get no quotes.

References pqxx::is_null(), pqxx::to_string(), pqxx::internal::wait_read(), and pqxx::internal::wait_write().

quote() [3/3]

std::string pqxx::connection::quote

(

binarystring const &

b

)

const

References pqxx::binarystring::data(), pqxx::connection::quote_raw(), and pqxx::binarystring::size().

quote_name() [1/2]

std::string pqxx::transaction_base::quote_name

(

std::string_view

identifier

)

const

Escape an SQL identifier for use in a query.

quote_name() [2/2]

std::string pqxx::connection::quote_name

(

std::string_view

identifier

)

const

Escape and quote an SQL identifier for use in a query.

Referenced by pqxx::connection::trace(), and pqxx::connection::unprepare().

quote_raw() [1/3]

std::string pqxx::transaction_base::quote_raw	(	unsigned char const	bin[],
		std::size_t	len
	)		const

Binary-escape and quote a binarystring for use as an SQL constant.

quote_raw() [2/3]

std::string pqxx::transaction_base::quote_raw

(

std::string const &

bin

)

const

References pqxx::transaction_base::conn(), and pqxx::connection::quote_raw().

quote_raw() [3/3]

std::string pqxx::connection::quote_raw	(	unsigned char const	bin[],
		std::size_t	len
	)		const

Escape and quote a string of binary data.

References pqxx::connection::esc_raw().

Referenced by pqxx::connection::quote(), and pqxx::transaction_base::quote_raw().

unesc_raw() [1/5]

std::string pqxx::transaction_base::unesc_raw

(

std::string const &

text

)

const

Unescape binary data, e.g. from a table field or notification payload.

Takes a binary string as escaped by PostgreSQL, and returns a restored copy of the original binary data.

unesc_raw() [2/5]

std::string pqxx::transaction_base::unesc_raw

(

char const *

text

)

const

Unescape binary data, e.g. from a table field or notification payload.

Takes a binary string as escaped by PostgreSQL, and returns a restored copy of the original binary data.

unesc_raw() [3/5]

std::string pqxx::connection::unesc_raw

(

std::string const &

text

)

const

Unescape binary data, e.g. from a table field or notification payload.

Takes a binary string as escaped by PostgreSQL, and returns a restored copy of the original binary data.

unesc_raw() [4/5]

std::string pqxx::connection::unesc_raw

(

zview

text

)

const

Unescape binary data, e.g. from a table field or notification payload.

Takes a binary string as escaped by PostgreSQL, and returns a restored copy of the original binary data.

References pqxx::zview::c_str(), and pqxx::internal::wait_read().

unesc_raw() [5/5]

std::string pqxx::connection::unesc_raw

(

char const

text[]

)

const

Unescape binary data, e.g. from a table field or notification payload.

Takes a binary string as escaped by PostgreSQL, and returns a restored copy of the original binary data.