Add escape/unescape functions

Makefile

@@ -13,7 +13,7 @@ endif
 PG_CPPFLAGS += $(shell $(PKG_CONFIG) --cflags-only-I liburiparser)
 SHLIB_LINK += $(shell $(PKG_CONFIG) --libs liburiparser)
 
-REGRESS = init test
+REGRESS = init test escape
 REGRESS_OPTS = --inputdir=test
 
 PGXS := $(shell $(PG_CONFIG) --pgxs)

README.md

@@ -126,3 +126,22 @@ Other functions:
     without normalization.  If you want to consider distinct URIs
     without regard for mostly irrelevant syntax differences, pass them
     through this function.
+
+- `uri_escape(text, space_to_plus boolean DEFAULT false, normalize_breaks boolean DEFAULT false) returns text`
+
+    Percent-encodes all reserved characters from the text.  This can
+    be useful for constructing URIs from strings.
+
+    If `space_to_plus` is true, then spaces are replaced by plus
+    signs.  If `normalize_breaks` is true, then line breaks are
+    converted to CR LF pairs (and subsequently percent-encoded).  Note
+    that these two conversions come from the HTML standard for
+    encoding form data but are not part of the specification for URIs.
+
+- `uri_unescape(text, plus_to_space boolean DEFAULT false, break_conversion boolean DEFAULT false) returns text`
+
+    Decodes all percent-encodings in the text.
+
+    If `plus_to_space` is true, then plus signs are converted to
+    spaces.  If `break_conversion` is true, then CR LF pairs are
+    converted to simple newlines (`\n`).

test/expected/escape.out

@@ -0,0 +1,99 @@
+SELECT uri_escape('foobar');
+ uri_escape 
+------------
+ foobar
+(1 row)
+
+SELECT uri_escape(':/?#[]@!$&''()*+,;=');
+                       uri_escape                       
+--------------------------------------------------------
+ %3A%2F%3F%23%5B%5D%40%21%24%26%27%28%29%2A%2B%2C%3B%3D
+(1 row)
+
+SELECT uri_escape('foo bar');
+ uri_escape 
+------------
+ foo%20bar
+(1 row)
+
+SELECT uri_escape('foo bar', space_to_plus := false);
+ uri_escape 
+------------
+ foo%20bar
+(1 row)
+
+SELECT uri_escape('foo bar', space_to_plus := true);
+ uri_escape 
+------------
+ foo+bar
+(1 row)
+
+SELECT uri_escape(E'foo\nbar');
+ uri_escape 
+------------
+ foo%0Abar
+(1 row)
+
+SELECT uri_escape(E'foo\nbar', normalize_breaks := false);
+ uri_escape 
+------------
+ foo%0Abar
+(1 row)
+
+SELECT uri_escape(E'foo\nbar', normalize_breaks := true);
+  uri_escape  
+--------------
+ foo%0D%0Abar
+(1 row)
+
+SELECT uri_unescape('foobar');
+ uri_unescape 
+--------------
+ foobar
+(1 row)
+
+SELECT uri_unescape('%3A%2F%3F%23%5B%5D%40%21%24%26%27%28%29%2A%2B%2C%3B%3D');
+    uri_unescape    
+--------------------
+ :/?#[]@!$&'()*+,;=
+(1 row)
+
+SELECT uri_unescape('foo+bar');
+ uri_unescape 
+--------------
+ foo+bar
+(1 row)
+
+SELECT uri_unescape('foo+bar', plus_to_space := false);
+ uri_unescape 
+--------------
+ foo+bar
+(1 row)
+
+SELECT uri_unescape('foo+bar', plus_to_space := true);
+ uri_unescape 
+--------------
+ foo bar
+(1 row)
+
+SELECT uri_unescape('foo%0D%0Abar');
+ uri_unescape 
+--------------
+ foo         +
+ bar
+(1 row)
+
+SELECT uri_unescape('foo%0D%0Abar', break_conversion := false);
+ uri_unescape 
+--------------
+ foo         +
+ bar
+(1 row)
+
+SELECT uri_unescape('foo%0D%0Abar', break_conversion := true);
+ uri_unescape 
+--------------
+ foo\r       +
+ bar
+(1 row)
+

test/sql/escape.sql

@@ -0,0 +1,21 @@
+SELECT uri_escape('foobar');
+SELECT uri_escape(':/?#[]@!$&''()*+,;=');
+
+SELECT uri_escape('foo bar');
+SELECT uri_escape('foo bar', space_to_plus := false);
+SELECT uri_escape('foo bar', space_to_plus := true);
+
+SELECT uri_escape(E'foo\nbar');
+SELECT uri_escape(E'foo\nbar', normalize_breaks := false);
+SELECT uri_escape(E'foo\nbar', normalize_breaks := true);
+
+SELECT uri_unescape('foobar');
+SELECT uri_unescape('%3A%2F%3F%23%5B%5D%40%21%24%26%27%28%29%2A%2B%2C%3B%3D');
+
+SELECT uri_unescape('foo+bar');
+SELECT uri_unescape('foo+bar', plus_to_space := false);
+SELECT uri_unescape('foo+bar', plus_to_space := true);
+
+SELECT uri_unescape('foo%0D%0Abar');
+SELECT uri_unescape('foo%0D%0Abar', break_conversion := false);
+SELECT uri_unescape('foo%0D%0Abar', break_conversion := true);

uri--0--1.sql

@@ -8,3 +8,15 @@ CREATE OPERATOR CLASS uri_ops_hash
     DEFAULT FOR TYPE uri USING hash AS
         OPERATOR        1       =,
         FUNCTION        1       uri_hash(uri);
+
+CREATE FUNCTION uri_escape(text, space_to_plus boolean DEFAULT false, normalize_breaks boolean DEFAULT false) RETURNS text
+    IMMUTABLE
+    STRICT
+    LANGUAGE C
+    AS '$libdir/uri';
+
+CREATE FUNCTION uri_unescape(text, plus_to_space boolean DEFAULT false, break_conversion boolean DEFAULT false) RETURNS text
+    IMMUTABLE
+    STRICT
+    LANGUAGE C
+    AS '$libdir/uri';

uri--1.sql

@@ -211,3 +211,15 @@ CREATE OPERATOR CLASS uri_ops_hash
     DEFAULT FOR TYPE uri USING hash AS
         OPERATOR        1       =,
         FUNCTION        1       uri_hash(uri);
+
+CREATE FUNCTION uri_escape(text, space_to_plus boolean DEFAULT false, normalize_breaks boolean DEFAULT false) RETURNS text
+    IMMUTABLE
+    STRICT
+    LANGUAGE C
+    AS '$libdir/uri';
+
+CREATE FUNCTION uri_unescape(text, plus_to_space boolean DEFAULT false, break_conversion boolean DEFAULT false) RETURNS text
+    IMMUTABLE
+    STRICT
+    LANGUAGE C
+    AS '$libdir/uri';

uri.c

@@ -455,3 +455,39 @@ uri_hash(PG_FUNCTION_ARGS)
 
 	return result;
 }
+
+PG_FUNCTION_INFO_V1(uri_escape);
+Datum
+uri_escape(PG_FUNCTION_ARGS)
+{
+	text *arg = PG_GETARG_TEXT_PP(0);
+	bool space_to_plus = PG_GETARG_BOOL(1);
+	bool normalize_breaks = PG_GETARG_BOOL(2);
+
+	size_t chars_required;
+	char *ret;
+
+	chars_required = (VARSIZE(arg) - 4) * (normalize_breaks ? 6 : 3) + 1;
+	ret = palloc(chars_required);
+	uriEscapeExA(VARDATA(arg),
+				 VARDATA(arg) + VARSIZE(arg) - 4,
+				 ret,
+				 space_to_plus, normalize_breaks);
+
+	PG_RETURN_TEXT_P(cstring_to_text(ret));
+}
+
+PG_FUNCTION_INFO_V1(uri_unescape);
+Datum
+uri_unescape(PG_FUNCTION_ARGS)
+{
+	text *arg = PG_GETARG_TEXT_PP(0);
+	bool plus_to_space = PG_GETARG_BOOL(1);
+	bool break_conversion = PG_GETARG_BOOL(2);
+
+	char *s = text_to_cstring(arg);
+
+	uriUnescapeInPlaceExA(s, plus_to_space, break_conversion);
+
+	PG_RETURN_TEXT_P(cstring_to_text(s));
+}