## Role |
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This class is used for spawning requests according given URL by matching them by regular expressions. |
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It is defined in `cppcms/url.h` header. |
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## Constructor |
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url_parser(); |
url_parser(worker_thread *w); |
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Creates new URL parser. First version creates standalone parser that can be used for any input string. Second derives the string from CGI variable `PATH_INFO`. |
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## General Recommendations |
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Always use callbacks to setup your url dispatching functions. |
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## Public Member Functions |
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### Setting Handlers |
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#### Binding to callback |
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void add(char const *expr,callbac_t ); |
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Binds expression to callback. `callback_t` is boost::function with 9 string parameters where: |
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- First 8 parameters are matched expressions --- $1,..,$8 |
in "perl" semantics. |
- Last 9 parameter is entry expression -- $0 in "perl" semantics. |
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For example: |
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class app : public application { |
void page(string id); |
... |
app(...) ... |
{ |
url.add("^/page/(\\d+)$", |
boost::bind(&app::page,this,_1)); |
} |
}; |
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Would setup callback to `page` member function and pass string id with matched number. |
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In order to remember in more easy way these parameters, macros $0, $1, ... $8 are defined in `url.h` header. Thus you can rewrite above lines as: |
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url.add("^/page/(\\d+)$", |
boost::bind(&app::page,this,$1)); |
In versions prior to CppCMS 0.0.4, you could use macros $0, $1, ... $8 that were defined in `url.h` header. They are |
depricated and should not be used becuase `$` in identifiers |
is not supported on some platforms like ARM. |
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#### Binding to ID |
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void add(char const *exp,int id); |
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Causes `url_parser::parse` return `id` when match had found. |
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#### Binding to other url\_parser: |
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void add(char const *exp,url_parser &url); |
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Forces `url_parser` to pass string to other parser if match was found. It may be used for faster matching urls. For example: |
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admin_url.add("^/admin/add_user$",...); |
admin_url.add("^/admin/remove_user$",...); |
... |
app_url.add("^/app/article/(\\d+)$",...); |
... |
url.add("^/admin/.*",admin_url); |
url.add("^/app/.*",app_url); |
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### Parsing URL |
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int parse(); |
int parse(string &s); |
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Parses URL using `s` or `PATH_INFO`. It returns |
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- `url_parser::ok` if callback was dispatched |
- `url_parser::not_found` if no match was found. |
- Other positive number if URL was associated with number and not callback. |
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If you using `url_parser` that returns id, you can find matched parameters using operator `[]`. For example: |
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url.add("^/page/(\\d+)$",1); |
switch(url.parse()) { |
case 1: id=url[1]; |
} |
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