ngx.re.sub
----------
**语法:** *newstr, n, err = ngx.re.sub(subject, regex, replace, options?)*
**环境:** *init_worker_by_lua*\**, set_by_lua*\**, rewrite_by_lua*\**, access_by_lua*\**, content_by_lua*\**, header_filter_by_lua*\**, body_filter_by_lua*\**, log_by_lua*\**, ngx.timer.*\*
使用 Perl 兼容正则表达式 `regex` 匹配字符串 `subject`,将第一个结果替换为字符串或函数类型参数 `replace`。可选参数 `options` 含义与 [ngx.re.match](#ngxrematch) 相同。
这个方法返回结果字符串以及成功替换的数量。当发生失败时,例如正则表达式或 `<replace>` 字符串参数语法错,将返回 `nil` 以及一个描述错误的字符串。
当 `replace` 是一个字符串时,它们被视为一个特殊字符串替换模板。例如:
```lua
local newstr, n, err = ngx.re.sub("hello, 1234", "([0-9])[0-9]", "[$0][$1]")
if newstr then
-- newstr == "hello, [12][1]34"
-- n == 1
else
ngx.log(ngx.ERR, "error: ", err)
return
end
```
其中 `$0` 指模板匹配的完整子字符串,`$1` 指第一个括号内匹配的子串。
花括号可以被用来从背景字符串中消除变量名歧义。
```lua
local newstr, n, err = ngx.re.sub("hello, 1234", "[0-9]", "${0}00")
-- newstr == "hello, 100234"
-- n == 1
```
要在 `replace` 中使用美元字符(`$`),可以使用另外一个该符号作为转义,例如,
```lua
local newstr, n, err = ngx.re.sub("hello, 1234", "[0-9]", "$$")
-- newstr == "hello, $234"
-- n == 1
```
不要使用反斜线转义美元字符;它不会象你想象的那样工作。
当 `replace` 参数是一个 "函数" 时,它将被通过参数 "匹配表" 调用,用来生成替换字符串。被送入 `replace` 函数的 "匹配表" 与 [ngx.re.match](#ngxrematch) 的返回值相同。例如:
```lua
local func = function (m)
return "[" .. m[0] .. "][" .. m[1] .. "]"
end
local newstr, n, err = ngx.re.sub("hello, 1234", "( [0-9] ) [0-9]", func, "x")
-- newstr == "hello, [12][1]34"
-- n == 1
```
在 `replace` 函数返回值中的美元字符没有任何特殊含义。
这个方法需要在 Nginx 中启用 PCRE 库。 ([Known Issue With Special Escaping Sequences](#special-escaping-sequences)).
这个功能最早出现在 `v0.2.1rc13` 版本中。
> English Source
**syntax:** *newstr, n, err = ngx.re.sub(subject, regex, replace, options?)*
**context:** *init_worker_by_lua*\**, set_by_lua*\**, rewrite_by_lua*\**, access_by_lua*\**, content_by_lua*\**, header_filter_by_lua*\**, body_filter_by_lua*\**, log_by_lua*\**, ngx.timer.*\*
Substitutes the first match of the Perl compatible regular expression `regex` on the `subject` argument string with the string or function argument `replace`. The optional `options` argument has exactly the same meaning as in [ngx.re.match](#ngxrematch).
This method returns the resulting new string as well as the number of successful substitutions. In case of failures, like syntax errors in the regular expressions or the `<replace>` string argument, it will return `nil` and a string describing the error.
When the `replace` is a string, then it is treated as a special template for string replacement. For example,
```lua
local newstr, n, err = ngx.re.sub("hello, 1234", "([0-9])[0-9]", "[$0][$1]")
if newstr then
-- newstr == "hello, [12][1]34"
-- n == 1
else
ngx.log(ngx.ERR, "error: ", err)
return
end
```
where `$0` referring to the whole substring matched by the pattern and `$1` referring to the first parenthesized capturing substring.
Curly braces can also be used to disambiguate variable names from the background string literals:
```lua
local newstr, n, err = ngx.re.sub("hello, 1234", "[0-9]", "${0}00")
-- newstr == "hello, 100234"
-- n == 1
```
Literal dollar sign characters (`$`) in the `replace` string argument can be escaped by another dollar sign, for instance,
```lua
local newstr, n, err = ngx.re.sub("hello, 1234", "[0-9]", "$$")
-- newstr == "hello, $234"
-- n == 1
```
Do not use backlashes to escape dollar signs; it will not work as expected.
When the `replace` argument is of type "function", then it will be invoked with the "match table" as the argument to generate the replace string literal for substitution. The "match table" fed into the `replace` function is exactly the same as the return value of [ngx.re.match](#ngxrematch). Here is an example:
```lua
local func = function (m)
return "[" .. m[0] .. "][" .. m[1] .. "]"
end
local newstr, n, err = ngx.re.sub("hello, 1234", "( [0-9] ) [0-9]", func, "x")
-- newstr == "hello, [12][1]34"
-- n == 1
```
The dollar sign characters in the return value of the `replace` function argument are not special at all.
This method requires the PCRE library enabled in Nginx. ([Known Issue With Special Escaping Sequences](#special-escaping-sequences)).
This feature was first introduced in the `v0.2.1rc13` release.
[返回目录](#nginx-api-for-lua)
- Name yuansheng-8.4 WenMing(√)
- Status yuansheng-8.6 WenMing(√)
- Version
- Synopsis yuansheng-8.6 WenMing(√)
- Description yuansheng-8.16 WenMing(√)
- Typical Uses yuansheng-8.16 WenMing(√)
- Nginx Compatibility yuansheng-8.17 WenMing(√)
- Installation yuansheng-8.17 WenMing(√)
- C Macro Configurations yuansheng-8.17 WenMing(√)
- Installation on Ubuntu 11.10 yuansheng-8.18
- Community
- English Mailing List
- Chinese Mailing List
- Code Repository yuansheng-8.20 WenMing(√)
- Bugs and Patches yuansheng-8.20 WenMing(√)
- Lua/LuaJIT bytecode support yuansheng-8.31
- System Environment Variable Support yuansheng-9.1
- HTTP 1.0 support lance-2015.8.13
- Statically Linking Pure Lua Modules yuansheng-9.1
- Nginx Worker内的数据共享 lance-2015.8.5
- Known Issues
- TCP socket connect operation issues yuansheng-9.2
- Lua Coroutine Yielding/Resuming yuansheng-9.2
- Lua Variable Scope yuansheng-9.2
- Locations Configured by Subrequest Directives of Other Modules lance-2015.8.12
- Cosockets Not Available Everywhere yuansheng-9.2
- 特别转义序列 lance-2015.8.5
- Mixing with SSI Not Supported yuansheng-9.2
- SPDY Mode Not Fully Supported yuansheng-9.2
- Missing data on short circuited requests yuansheng-9.2
- TODO yuansheng-9.3
- Changes yuansheng-9.3 WenMing(√)
- Test Suite yuansheng-9.3
- Copyright and License yuansheng-9.3
- See Also yuansheng-9.3
- Directives yuansheng-9.3
- Nginx API for Lua yuansheng-9.3
- Obsolete Sections yuansheng-9.3
- lua_use_default_type hambut 2015.8.5
- lua_code_cache hambut 2015.8.5
- lua_regex_cache_max_entries yuansheng-9.3
- lua_regex_match_limit yuansheng-9.3
- lua_package_path yuansheng-9.4
- lua_package_cpath yuansheng-9.4
- init_by_lua yuansheng-9.4
- init_by_lua_file yuansheng-9.4
- init_worker_by_lua yuansheng-9.6
- init_worker_by_lua_file yuansheng-9.6
- set_by_lua yuansheng-9.6
- set_by_lua_file yuansheng-9.6
- content_by_lua dengshiyong 2015.8.12 WenMing(√)
- content_by_lua_file yuansheng-9.19
- rewrite_by_lua yuansheng-9.19
- rewrite_by_lua_file yuansheng-9.19
- access_by_lua yuansheng-9.27
- access_by_lua_file yuansheng-9.28
- header_filter_by_lua liujinxuan 2015.9.1
- header_filter_by_lua_file yuansheng-9.28
- body_filter_by_lua yuansheng-9.28
- body_filter_by_lua_file yuansheng-9.28
- log_by_lua yuansheng-9.28
- log_by_lua_file yuansheng-9.28
- lua_need_request_body yuansheng-9.28
- lua_shared_dict lance-2015.8.20
- lua_socket_connect_timeout yuansheng-9.28
- lua_socket_send_timeout yuansheng-9.28
- lua_socket_send_lowat yuansheng-9.28
- lua_socket_read_timeout yuansheng-9.28
- lua_socket_buffer_size yuansheng-9.28
- lua_socket_pool_size yuansheng-9.28
- lua_socket_keepalive_timeout yuansheng-9.28
- lua_socket_log_errors yuansheng-9.28
- lua_ssl_ciphers yuansheng-9.29
- lua_ssl_crl yuansheng-9.29
- lua_ssl_protocols yuansheng-9.29
- lua_ssl_trusted_certificate yuansheng-9.29
- lua_ssl_verify_depth yuansheng-9.29
- lua_http10_buffering yuansheng-9.29
- rewrite_by_lua_no_postpone yuansheng-9.29
- lua_transform_underscores_in_response_headers yuansheng-9.29
- lua_check_client_abort yuansheng-9.29
- lua_max_pending_timers yuansheng-9.29
- lua_max_running_timers yuansheng-9.29
- ngx.arg lance-2015.8.19
- ngx.var.VARIABLE lance-2015.8.19
- Core constants lance-2015.8.14 WenMing(√)
- HTTP method constants lance-2015.8.13
- HTTP status constants lance-2015.8.13
- Nginx log level constants lance-2015.8.13
- print lance-2015.8.14
- ngx.ctx lance-2015.8.14
- ngx.location.capture lance-2015.8.11
- ngx.location.capture_multi lance-2015.8.11
- ngx.status lance-2015.8.18 yuansheng(√)
- ngx.header.HEADER lance-2015.9.6 yuansheng(√)
- ngx.resp.get_headers lance-2015.9.7 yuansheng(√)
- ngx.req.start_time lance-2015.9.9 yuansheng(√)
- ngx.req.http_version lance-2015.9.9 yuansheng(√)
- ngx.req.raw_header lance-2015.9.9 yuansheng(√)
- ngx.req.get_method lance-2015.9.9 yuansheng(√)
- ngx.req.set_method lance-2015.9.9 yuansheng(√)
- ngx.req.set_uri lance-2015.9.9
- ngx.req.set_uri_args lance-2015.9.10
- ngx.req.get_uri_args lance-2015.9.10
- ngx.req.get_post_args lance-2015.9.10
- ngx.req.get_headers lance-2015.9.11
- ngx.req.set_header lance-2015.9.14
- ngx.req.clear_header lance-2015.9.14
- ngx.req.read_body lance-2015.9.16
- ngx.req.discard_body lance-2015.9.24
- ngx.req.get_body_data lance-2015.9.24
- ngx.req.get_body_file lance-2015.9.28
- ngx.req.set_body_data lance-2015.9.28
- ngx.req.set_body_file lance-2015.9.28
- ngx.req.init_body lance-2015.9.28
- ngx.req.append_body lance-2015.9.28
- ngx.req.finish_body lance-2015.9.28
- ngx.req.socket yuansheng-10.12
- ngx.exec yuansheng-10.12
- ngx.redirect yuansheng-10.12
- ngx.send_headers yuansheng-10.12
- ngx.headers_sent yuansheng-10.12
- ngx.print lance-2015.8.7
- ngx.say lance-2015.8.7
- ngx.log lance-2015.8.13
- ngx.flush lance-2015.8.13
- ngx.exit lance-2015.8.13
- ngx.eof lance-2015.8.18
- ngx.sleep lance-2015.8.18
- ngx.escape_uri lance-2015.8.18
- ngx.unescape_uri lance-2015.8.18
- ngx.encode_args lance-2015.8.18
- ngx.decode_args lance-2015.8.18
- ngx.encode_base64 hambut-2015.9.9
- ngx.decode_base64 hambut-2015.9.9
- ngx.crc32_short hambut-2015.9.9
- ngx.crc32_long hambut-2015.9.9
- ngx.hmac_sha1 hambut-2015.9.9
- ngx.md5 hambut-2015.9.9
- ngx.md5_bin hambut-2015.9.9
- ngx.sha1_bin hambut-2015.9.9
- ngx.quote_sql_str hambut-2015.9.9
- ngx.today bells-2015.8.8
- ngx.time bells-2015.8.22
- ngx.now bells-2015.8.22
- ngx.update_time bells-2015.8.16
- ngx.localtime bells-2015.8.22
- ngx.utctime bells-2015.8.22
- ngx.cookie_time yuansheng-10.12
- ngx.http_time yuansheng-10.10
- ngx.parse_http_time yuansheng-10.10
- ngx.is_subrequest yuansheng-10.8
- ngx.re.match lance-2015.8.6
- ngx.re.find lance-2015.8.6
- ngx.re.gmatch lance-2015.8.6
- ngx.re.sub lance-2015.8.6
- ngx.re.gsub lance-2015.8.6
- ngx.shared.DICT lance-2015.8.10
- ngx.shared.DICT.get lance-2015.8.10
- ngx.shared.DICT.get_stale lance-2015.8.10
- ngx.shared.DICT.set lance-2015.8.10
- ngx.shared.DICT.safe_set lance-2015.8.10
- ngx.shared.DICT.add lance-2015.8.10
- ngx.shared.DICT.safe_add lance-2015.8.10
- ngx.shared.DICT.replace lance-2015.8.10
- ngx.shared.DICT.delete lance-2015.8.10
- ngx.shared.DICT.incr lance-2015.8.10
- ngx.shared.DICT.flush_all lance-2015.8.10
- ngx.shared.DICT.flush_expired lance-2015.8.10
- ngx.shared.DICT.get_keys lance-2015.8.10
- ngx.socket.udp yuansheng-10.8
- udpsock:setpeername yuansheng-10.8
- udpsock:send yuansheng-10.8
- udpsock:receive yuansheng-10.8
- udpsock:close yuansheng-10.8
- udpsock:settimeout yuansheng-10.8
- ngx.socket.tcp yuansheng-10.7
- tcpsock:connect yuansheng-10.7
- tcpsock:sslhandshake yuansheng-10.7
- tcpsock:send yuansheng-10.7
- tcpsock:receive yuansheng-10.5
- tcpsock:receiveuntil yuansheng-10.5
- tcpsock:close yuansheng-10.5
- tcpsock:settimeout yuansheng-10.5
- tcpsock:setoption yuansheng-10.5
- tcpsock:setkeepalive yuansheng-10.5
- tcpsock:getreusedtimes yuansheng-10.5
- ngx.socket.connect yuansheng-10.4
- ngx.get_phase yuansheng-10.2
- ngx.thread.spawn yuansheng-10.2
- ngx.thread.wait yuansheng-10.4
- ngx.thread.kill yuansheng-10.4
- ngx.on_abort yuansheng-10.2
- ngx.timer.at yuansheng-10.1
- ngx.config.debug yuansheng-9.30
- ngx.config.prefix yuansheng-9.30
- ngx.config.nginx_version yuansheng-9.30
- ngx.config.nginx_configure yuansheng-9.30
- ngx.config.ngx_lua_version yuansheng-9.30
- ngx.worker.exiting yuansheng-9.30
- ngx.worker.pid yuansheng-9.30
- ndk.set_var.DIRECTIVE yuansheng-9.30
- coroutine.create yuansheng-9.30
- coroutine.resume yuansheng-9.30
- coroutine.yield yuansheng-9.30
- coroutine.wrap yuansheng-9.30
- coroutine.running yuansheng-9.30
- coroutine.status yuansheng-9.30