I need to parse a URL to get the protocol, host, path, and query in an application I am writing in C++. The application is intended to be cross-platform. I'm surprised I can't find anything that does this in the boost or POCO libraries. Is it somewhere obvious I'm not looking? Any suggestions on appropriate open source libs? Or is this something I just have to do my self? It's not super complicated but it seems like such a common task I am surprised there isn't a common solution.
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问题:
回答1:
There is a library that's proposed for Boost inclusion and allows you to parse HTTP URI's easily. It uses Boost.Spirit and is also released under the Boost Software License. The library is cpp-netlib which you can find the documentation for at http://cpp-netlib.github.com/ -- you can download the latest release from http://github.com/cpp-netlib/cpp-netlib/downloads .
The relevant type you'll want to use is boost::network::http::uri and is documented here.
回答2:
Terribly sorry, couldn't help it. :s
url.hh
#ifndef URL_HH_ #define URL_HH_ #include <string> struct url { url(const std::string& url_s); // omitted copy, ==, accessors, ... private: void parse(const std::string& url_s); private: std::string protocol_, host_, path_, query_; }; #endif /* URL_HH_ */ url.cc
#include "url.hh" #include <string> #include <algorithm> #include <cctype> #include <functional> using namespace std; // ctors, copy, equality, ... void url::parse(const string& url_s) { const string prot_end("://"); string::const_iterator prot_i = search(url_s.begin(), url_s.end(), prot_end.begin(), prot_end.end()); protocol_.reserve(distance(url_s.begin(), prot_i)); transform(url_s.begin(), prot_i, back_inserter(protocol_), ptr_fun<int,int>(tolower)); // protocol is icase if( prot_i == url_s.end() ) return; advance(prot_i, prot_end.length()); string::const_iterator path_i = find(prot_i, url_s.end(), '/'); host_.reserve(distance(prot_i, path_i)); transform(prot_i, path_i, back_inserter(host_), ptr_fun<int,int>(tolower)); // host is icase string::const_iterator query_i = find(path_i, url_s.end(), '?'); path_.assign(path_i, query_i); if( query_i != url_s.end() ) ++query_i; query_.assign(query_i, url_s.end()); } main.cc
// ... url u("HTTP://stackoverflow.com/questions/2616011/parse-a.py?url=1"); cout << u.protocol() << '\t' << u.host() << ... 回答3:
Wstring version of above, added other fields I needed. Could definitely be refined, but good enough for my purposes.
#include <string> #include <algorithm> // find struct Uri { public: std::wstring QueryString, Path, Protocol, Host, Port; static Uri Parse(const std::wstring &uri) { Uri result; typedef std::wstring::const_iterator iterator_t; if (uri.length() == 0) return result; iterator_t uriEnd = uri.end(); // get query start iterator_t queryStart = std::find(uri.begin(), uriEnd, L'?'); // protocol iterator_t protocolStart = uri.begin(); iterator_t protocolEnd = std::find(protocolStart, uriEnd, L':'); //"://"); if (protocolEnd != uriEnd) { std::wstring prot = &*(protocolEnd); if ((prot.length() > 3) && (prot.substr(0, 3) == L"://")) { result.Protocol = std::wstring(protocolStart, protocolEnd); protocolEnd += 3; // :// } else protocolEnd = uri.begin(); // no protocol } else protocolEnd = uri.begin(); // no protocol // host iterator_t hostStart = protocolEnd; iterator_t pathStart = std::find(hostStart, uriEnd, L'/'); // get pathStart iterator_t hostEnd = std::find(protocolEnd, (pathStart != uriEnd) ? pathStart : queryStart, L':'); // check for port result.Host = std::wstring(hostStart, hostEnd); // port if ((hostEnd != uriEnd) && ((&*(hostEnd))[0] == L':')) // we have a port { hostEnd++; iterator_t portEnd = (pathStart != uriEnd) ? pathStart : queryStart; result.Port = std::wstring(hostEnd, portEnd); } // path if (pathStart != uriEnd) result.Path = std::wstring(pathStart, queryStart); // query if (queryStart != uriEnd) result.QueryString = std::wstring(queryStart, uri.end()); return result; } // Parse }; // uri Tests/Usage
Uri u0 = Uri::Parse(L"http://localhost:80/foo.html?&q=1:2:3"); Uri u1 = Uri::Parse(L"https://localhost:80/foo.html?&q=1"); Uri u2 = Uri::Parse(L"localhost/foo"); Uri u3 = Uri::Parse(L"https://localhost/foo"); Uri u4 = Uri::Parse(L"localhost:8080"); Uri u5 = Uri::Parse(L"localhost?&foo=1"); Uri u6 = Uri::Parse(L"localhost?&foo=1:2:3"); u0.QueryString, u0.Path, u0.Protocol, u0.Host, u0.Port.... 回答4:
For completeness, there is one written in C that you could use (with a little wrapping, no doubt): http://uriparser.sourceforge.net/
[RFC-compliant and supports Unicode]
Here's a very basic wrapper I've been using for simply grabbing the results of a parse.
#include <string> #include <uriparser/Uri.h> namespace uriparser { class Uri //: boost::noncopyable { public: Uri(std::string uri) : uri_(uri) { UriParserStateA state_; state_.uri = &uriParse_; isValid_ = uriParseUriA(&state_, uri_.c_str()) == URI_SUCCESS; } ~Uri() { uriFreeUriMembersA(&uriParse_); } bool isValid() const { return isValid_; } std::string scheme() const { return fromRange(uriParse_.scheme); } std::string host() const { return fromRange(uriParse_.hostText); } std::string port() const { return fromRange(uriParse_.portText); } std::string path() const { return fromList(uriParse_.pathHead, "/"); } std::string query() const { return fromRange(uriParse_.query); } std::string fragment() const { return fromRange(uriParse_.fragment); } private: std::string uri_; UriUriA uriParse_; bool isValid_; std::string fromRange(const UriTextRangeA & rng) const { return std::string(rng.first, rng.afterLast); } std::string fromList(UriPathSegmentA * xs, const std::string & delim) const { UriPathSegmentStructA * head(xs); std::string accum; while (head) { accum += delim + fromRange(head->text); head = head->next; } return accum; } }; } 回答5:
POCO's URI class can parse URLs for you. The following example is shortened version of the one in POCO URI and UUID slides:
#include "Poco/URI.h" #include <iostream> int main(int argc, char** argv) { Poco::URI uri1("http://www.appinf.com:88/sample?example-query#frag"); std::string scheme(uri1.getScheme()); // "http" std::string auth(uri1.getAuthority()); // "www.appinf.com:88" std::string host(uri1.getHost()); // "www.appinf.com" unsigned short port = uri1.getPort(); // 88 std::string path(uri1.getPath()); // "/sample" std::string query(uri1.getQuery()); // "example-query" std::string frag(uri1.getFragment()); // "frag" std::string pathEtc(uri1.getPathEtc()); // "/sample?example-query#frag" return 0; } 回答6:
The Poco library now has a class for dissecting URI's and feeding back the host, path segments and query string etc.
回答7:
Facebook's Folly library can do the job for you easily. Simply use the Uri class:
#include <folly/Uri.h> int main() { folly::Uri folly("https://code.facebook.com/posts/177011135812493/"); folly.scheme(); // https folly.host(); // code.facebook.com folly.path(); // posts/177011135812493/ } 回答8:
//sudo apt-get install libboost-all-dev; #install boost //g++ urlregex.cpp -lboost_regex; #compile #include <string> #include <iostream> #include <boost/regex.hpp> using namespace std; int main(int argc, char* argv[]) { string url="https://www.google.com:443/webhp?gws_rd=ssl#q=cpp"; boost::regex ex("(http|https)://([^/ :]+):?([^/ ]*)(/?[^ #?]*)\\x3f?([^ #]*)#?([^ ]*)"); boost::cmatch what; if(regex_match(url.c_str(), what, ex)) { cout << "protocol: " << string(what[1].first, what[1].second) << endl; cout << "domain: " << string(what[2].first, what[2].second) << endl; cout << "port: " << string(what[3].first, what[3].second) << endl; cout << "path: " << string(what[4].first, what[4].second) << endl; cout << "query: " << string(what[5].first, what[5].second) << endl; cout << "fragment: " << string(what[6].first, what[6].second) << endl; } return 0; } 回答9:
QT has QUrl for this. GNOME has SoupURI in libsoup, which you'll probably find a little more light-weight.
回答10:
Also of interest could be http://code.google.com/p/uri-grammar/ which like Dean Michael's netlib uses boost spirit to parse a URI. Came across it at Simple expression parser example using Boost::Spirit?
回答11:
There is the newly released google-url lib:
http://code.google.com/p/google-url/
The library provides a low-level url parsing API as well as a higher-level abstraction called GURL. Here's an example using that:
#include <googleurl\src\gurl.h> wchar_t url[] = L"http://www.facebook.com"; GURL parsedUrl (url); assert(parsedUrl.DomainIs("facebook.com")); Two small complaints I have with it: (1) it wants to use ICU by default to deal with different string encodings and (2) it makes some assumptions about logging (but I think they can be disabled). In other words, the library is not completely stand-alone as it exists, but I think it's still a good basis to start with, especially if you are already using ICU.
回答12:
This library is very tiny and lightweight: https://github.com/corporateshark/LUrlParser
However, it is parsing only, no URL normalization/validation.
回答13:
I was looking for easy standalone URI library for C++ too. Being unable to find one i took URI class from Poco, recomended in this topic, and made it independent by making few modifications to original source files. Made of only 2 source files and doesnt require any exgernal libraries, only uses few headers from STL. I've done some testing with GCC and MS compilers and put it here on my website: http://ikk.byethost9.com/index.php?MainMenu=hef_uri_syntax It has renamed namespace Poco -> hef and renamed main class URI -> HfURISyntax. Its enncouraged to rename these when using in Your own projects. (Original copyright included. There is a text document that contains summary of modifications.)
回答14:
You could try the open-source library called C++ REST SDK (created by Microsoft, distributed under the Apache License 2.0). It can be built for several platforms including Windows, Linux, OSX, iOS, Android). There is a class called web::uri where you put in a string and can retrieve individual URL components. Here is a code sample (tested on Windows):
#include <cpprest/base_uri.h> #include <iostream> #include <ostream> web::uri sample_uri( L"http://dummyuser@localhost:7777/dummypath?dummyquery#dummyfragment" ); std::wcout << L"scheme: " << sample_uri.scheme() << std::endl; std::wcout << L"user: " << sample_uri.user_info() << std::endl; std::wcout << L"host: " << sample_uri.host() << std::endl; std::wcout << L"port: " << sample_uri.port() << std::endl; std::wcout << L"path: " << sample_uri.path() << std::endl; std::wcout << L"query: " << sample_uri.query() << std::endl; std::wcout << L"fragment: " << sample_uri.fragment() << std::endl; The output will be:
scheme: http user: dummyuser host: localhost port: 7777 path: /dummypath query: dummyquery fragment: dummyfragment There are also other easy-to-use methods, e.g. to access individual attribute/value pairs from the query, split the path into components, etc.
回答15:
There is yet another library https://snapwebsites.org/project/libtld which handles all possible top level domains and URI shema