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Re: [Boost-users] Help with the steps needed to handle a large POST file upload
by Javier Sánchez 27 Mar '20

27 Mar '20

I'd suggest you take a look into the SmartUpload class in Java, I > understand it's a third party contribution. POST's that have attachments > have "parts" of their contents which are identified by their headers in the > MIME type. The logical thing to do is to loop through the several parts > and identify the one that you are expecting. If you are not exactly > looking after specific code I'd suggest you consult the RFC's related to > those types of contents in POST requests. There you'll have the key you > need. Regards. >

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Help with the steps needed to handle a large POST file upload (Boost Beast)
by Bill Moo 25 Mar '20

25 Mar '20

For anyone that has read my previous post, it will be evident from this request that I've not made any real progress of this, with my level of frustration rising, so I'm turning to the community again for assistance. Is anyone able to provide me with the steps I need to take to be able to download and save a 5 to 10 MB binary file submitted via a POST verb. I have tried many things but I simply can't get it to work, or work out the correct process. I'm not asking for code but the steps I need and where to take them in order to achieve my goal. Due to the size of the uploads I know I need to use a parser and I have search the internet for such an example to no avail so I would appreciate your help with this. The server I'm using is a single strand async implementation, derived from the Beast examples. -- Regards, Bill

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[gsoc] Example of exceptional project proposal
by Mateusz Loskot 24 Mar '20

24 Mar '20

...as it is not Dear students, if you aim to submit proposals like this, then please don't bother polluting the GSoC space with such rubbish. Please, let's display some minimum of professionalism and respect to each other. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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Uploading a file to a Boost Beast Server
by Bill Moo 24 Mar '20

24 Mar '20

I am using Beast 277 and code from the advanced server example as the basis for my own one. As part of the functionality I need to allow users the ability to upload a file to the server via their browser. So I had a look at the 'Deferred Body Type' in the examples provided but I can't see how I can make use of it in my own server, although I have tried but fall foul of the SyncReadStream. Is there a working example anywhere of how I can capture and save a file uploaded to the server by a user please. -- Bill

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asio, beast and concepts
by David P. Riedel 24 Mar '20

24 Mar '20

Hi I have been experimenting with some C++20 concepts code. Currently, I have a program which uses beast and asio to do some network file transfers. I was thinking of adding a small piece of code to my code which includes a concept. Prior to doing this, I tried building the beast tests from the 1.72 version with concepts enabled in the compiler. I got lots of errors such as the one below. beast/http/write.cpp:313:44: error: use of ‘auto boost::beast::http::async_write(AsyncWriteStream&, const boost::beast::http::message<isRequest, Body, Fields>&, WriteHandler&&, typename std::enable_if<(! boost::beast::http::is_mutable_body_writer<Body>::value)>::type*) [with AsyncWriteStream = boost::beast::test::stream; bool isRequest = false; Body = boost::beast::http::basic_string_body<char>; Fields = boost::beast::http::basic_fields<std::allocator<char> >; WriteHandler = boost::asio::basic_yield_context<boost::asio::executor_binder<void (*)(), boost::asio::executor> >; typename std::enable_if<(! boost::beast::http::is_mutable_body_writer<Body>::value)>::type = void]’ before deduction of ‘auto’ 313 | async_write(ts, m, do_yield[ec]); | ^ Are beast and asio not concepts ready? Or am I missing something? Is there some flag I need to set? My set up: boost: 1.72 gcc: 9.3 I added -std=c++2a -fconcepts to compile flags in my user-config.jam file to enable compiler concepts support. I have no problems using these compiler flags with other non-boost code. Thanks

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[Newbie][Interprocess] Placing a boost interprocess vector in an existing (not managed) shared memory
by Gaier, Bjoern 17 Mar '20

17 Mar '20

Hello Boost-Mailing-List, I have a question about the boost interprocess library - and I hope I can explain it correctly. I looked at the "Quick guide for the impatient" about the interprocess library - but I'm not sure if I can use this for our purpose. The main goal is to insert a STL vector (or different container) in a predefined portion of an already existing shared memory. The main problem is, that we cannot use the managed_shared_memory code from boost, because we rely on a different API to allocate the shared memory between Windows and other devices. Also the container should be placed at a fixed offset inside the created shared memory. I'm a complete newbie with boost and the interprocess library, that is why I'm not sure which interface I have to provide for the interprocess vector to be setup correctly. I hoped I could do something like: new (srh_mem_base + offset) boost::interprocess::vector<allocator>; I tried looking into the headers of the library to get an idea of that, but I honestly got lost. I'm really sorry if this a stupid or obvious question - and I thank for any help in advance! Kind greetings Björn Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima. Junichi Tajika

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Is iterator_facade still relevant in C++11, C++17?
by Mateusz Loskot 14 Mar '20

14 Mar '20

Hi, This is a bit theoretical question, but I'd like to collect some opinions. Considering sequence of C++ versions, around where, if at all, boost::iterator_facade shines less and becomes less relevant? In other words: - If you had to implement iterators in C++11, would you use it? - If you had to implement iterators in C++17, would you use it? Has anyone observed performance issues when using iterator_facade? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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bimap: one to many
by MM 13 Mar '20

13 Mar '20

Hello I want a collection to store a relationship N to M like so: Item of type A Item of type B A1 B1,B2,B3 A2 B4 A3 B1 and I would like a convenient way to get from a A instance to the list of B instances, and vice versa, from a given B instance to the list of A instances. At runtime, the A objects are created first, then a list of B objects is created. Later, B objects get modified asynchronously and that modification need to update the relevant A instances what container to use? boost::bimap< unordered_set<A*> , unordered_set<B*> > ?

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Failing to build Boost
by MANAV KUMAR 13 Mar '20

13 Mar '20

Hi , I am Manav Kumar. I was trying to install boost version 1.72 on my system Mac OSX. But after installing the package from it’s website and running the ./bootstrap.sh command while being in it’s directory I am getting the following error :- ' Building Boost.Build engine with toolset clang… Failed to build Boost.Build build engine Consult ‘bootstrap.log’ for more details. ‘ And I am hardly able to understand the bootstrap.log file to figure out the problem. Somebody please help me with it. Regards Manav

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shared memory objects limitation in Windows 10
by Shen, Chang (MSFC-EV43) 11 Mar '20

11 Mar '20

Hi All I am testing my class using boost. The class has a shared_memory_object member : class X { char* m_buffer; boost::interprocess::shared_memory_object *m_sram; public X(char *name) { m_buffer = (char*)malloc(128); m_sram = new(std::nothrow) boost::interprocess::shared_memory_object(boost::interprocess::open_or_create_t, name, boost::interprocess::mode_t::read_write); } } int main() { std::vector<X*> xlist; for(int i=0;i<1500;i++) { std::string name = std::to_string(i); X *x = new(std::nothrow) (name.c_str()); xlist.push_back(x); } return 0; } I test the class in Window 10 using MinGW 32bit compiler. g++ (MinGW.org GCC-8.2.0-3) 8.2.0 Copyright (C) 2018 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. I find that I only can create 1463 X objects. 1464th object will throw exception: Dynamic exception type: boost::interprocess::interprocess_exception std::exception::what: WinApi FormatMessage returned error. Why this limitation?

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