final public releaseskytools_2_1

1 files changed, 156 insertions, 0 deletions

diff --git a/python/skytools/quoting.py b/python/skytools/quoting.py
new file mode 100644
index 00000000..96b0b022
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+++ b/python/skytools/quoting.py
@@ -0,0 +1,156 @@
+# quoting.py
+
+"""Various helpers for string quoting/unquoting."""
+
+import psycopg, urllib, re
+
+# 
+# SQL quoting
+#
+
+def quote_literal(s):
+    """Quote a literal value for SQL.
+    
+    Surronds it with single-quotes.
+    """
+
+    if s == None:
+        return "null"
+    s = psycopg.QuotedString(str(s))
+    return str(s)
+
+def quote_copy(s):
+    """Quoting for copy command."""
+
+    if s == None:
+        return "\\N"
+    s = str(s)
+    s = s.replace("\\", "\\\\")
+    s = s.replace("\t", "\\t")
+    s = s.replace("\n", "\\n")
+    s = s.replace("\r", "\\r")
+    return s
+
+def quote_bytea_raw(s):
+    """Quoting for bytea parser."""
+
+    if s == None:
+        return None
+    return s.replace("\\", "\\\\").replace("\0", "\\000")
+
+def quote_bytea_literal(s):
+    """Quote bytea for regular SQL."""
+
+    return quote_literal(quote_bytea_raw(s))
+
+def quote_bytea_copy(s):
+    """Quote bytea for COPY."""
+
+    return quote_copy(quote_bytea_raw(s))
+
+def quote_statement(sql, dict):
+    """Quote whose statement.
+
+    Data values are taken from dict.
+    """
+    xdict = {}
+    for k, v in dict.items():
+        xdict[k] = quote_literal(v)
+    return sql % xdict
+
+#
+# quoting for JSON strings
+#
+
+_jsre = re.compile(r'[\x00-\x1F\\/"]')
+_jsmap = { "\b": "\\b", "\f": "\\f", "\n": "\\n", "\r": "\\r",
+    "\t": "\\t", "\\": "\\\\", '"': '\\"',
+    "/": "\\/",   # to avoid html attacks
+}
+
+def _json_quote_char(m):
+    c = m.group(0)
+    try:
+        return _jsmap[c]
+    except KeyError:
+        return r"\u%04x" % ord(c)
+
+def quote_json(s):
+    """JSON style quoting."""
+    if s is None:
+        return "null"
+    return '"%s"' % _jsre.sub(_json_quote_char, s)
+
+#
+# Database specific urlencode and urldecode.
+#
+
+def db_urlencode(dict):
+    """Database specific urlencode.
+
+    Encode None as key without '='.  That means that in "foo&bar=",
+    foo is NULL and bar is empty string.
+    """
+
+    elem_list = []
+    for k, v in dict.items():
+        if v is None:
+            elem = urllib.quote_plus(str(k))
+        else:
+            elem = urllib.quote_plus(str(k)) + '=' + urllib.quote_plus(str(v))
+        elem_list.append(elem)
+    return '&'.join(elem_list)
+
+def db_urldecode(qs):
+    """Database specific urldecode.
+
+    Decode key without '=' as None.
+    This also does not support one key several times.
+    """
+
+    res = {}
+    for elem in qs.split('&'):
+        if not elem:
+            continue
+        pair = elem.split('=', 1)
+        name = urllib.unquote_plus(pair[0])
+        if len(pair) == 1:
+            res[name] = None
+        else:
+            res[name] = urllib.unquote_plus(pair[1])
+    return res
+
+#
+# Remove C-like backslash escapes
+#
+
+_esc_re = r"\\([0-7][0-7][0-7]|.)"
+_esc_rc = re.compile(_esc_re)
+_esc_map = {
+    't': '\t',
+    'n': '\n',
+    'r': '\r',
+    'a': '\a',
+    'b': '\b',
+    "'": "'",
+    '"': '"',
+    '\\': '\\',
+}
+
+def _sub_unescape(m):
+    v = m.group(1)
+    if len(v) == 1:
+        return _esc_map[v]
+    else:
+        return chr(int(v, 8))
+
+def unescape(val):
+    """Removes C-style escapes from string."""
+    return _esc_rc.sub(_sub_unescape, val)
+
+def unescape_copy(val):
+    """Removes C-style escapes, also converts "\N" to None."""
+    if val == r"\N":
+        return None
+    return unescape(val)
+