Libpff binary system 2018
Currently, I am playing around with WebSockets. This is due to an application idea I have in my mind which requires a bidirectional connection between browser and server with low latency. The communication will happen in a stream-like fashion at low bandwidth. The future belongs to WebSockets. Implemented directly in the browser they are providing a much lower level network connection between the browser and the server than HTTP — without any plugin.
WebSockets still work on a layer above TCP, but low latency and efficient data transport in both directions is warranted in a TCP-like fashion. Therefore, real-time application developers are very keen to use WebSockets. Most importantly, there is a huge lack of documentation how to use these. Simple so far, but the main focus while realizing this is on selecting the right tools for the taskas there is already a lot of stuff out there — some very good, undocumented and hidden things, some totally overloaded things, and some bad things.
I tried to fulfill the following conditions:. While doing so, the goal was to handle all underlying stream errors as well as file opening errors, and to emit as precise error messages as possible. In a high-level programming language such as Python this level of reliability and usability is not difficult to obtain. Proper handling of the stream error bits eofbitfailbitand badbit requires a tremendous amount of care, as discussed for example herehereand hereand finally at cplusplus.
It is worth mentioning that although cplusplus. When it comes to the idea of providing meaningful error messages, things become quite complicated. Proper evaluation of errnorespectively perrorin response to the stream error bits is not a trivial task as can be inferred from discussions like this and this.
From these discussions we learn that most of the related uncertainty comes from a lack of centralized documentation or even missing documentation. We for example expect that when fopen returns NULLerrno is set to something meaningful. But where is this actually documented? In order to understand the relation between the language and operating system constructs involved, I performed quite some research and testing.
Of course there are many obvious and non-obvious ways to write unreliable code. To name, explain, and share those with the community is the goal of this article. We all know that re-using established recipes saves time and improves software quality in the long-term. Update January 18th, It is one of the most-visited articles on my website. Thanks for commenting and sharing! Update July 7th, I revised the article after an important insight provided by Alexandre Duret-Lutz confer comments.
Therefore this short post. However, I most often use a more intelligent command for removing solvent in general:. Currently, I am looking into gevent — a nicely performing networking library for Python, based on the brilliant idea of greenlets. I try to use this for WebSocket communication with browsers. As of today, WebSockets are still not available or disabled in some browsers. As a first step, it always tries to receive a so-called socket policy file from the same server the SWF file was received from; on port This policy file tells the client from whom he is allowed to receive data.
Today, I present a simple server based on gevent providing this policy file for connecting Flash clients. I compiled both — libpdf and grace — as non-privileged user: I tried to fulfill the following conditions: For removing hydrogensbest use a selection:
11965e-05 8. 16333e-08 0. 79692 6.