Yara: Yet Another RSS Aggregator

Yara is a fast, embeddable RSS aggregator and parser. It is written in C++ and exposes a very simple API in C.
- For the time being, the C API consists of the following functions:
-

- /* returns 0 on success */
- int Yara_render(
-     const char * target_filename /* name of the file to render into */,
-     const char * template_filename /* compiled template to use */,
-     const char * rss_xml /* RSS stream to parse and render */);
-
- /* returns 0 on success */
- int Yara_compileTemplate(
-     const char * target_filename /* name of the file to save the compiled template to */,
-     const char * header_filename /* name of the file with the header template */,
-     const char * footer_filename /* name of the file with the footer template */,
-     const char * item_filename /* name of the file with the item template */);
-
- /* returns a pointer to the most recent error message */
- const char * Yara_getLastError();
-
- /* pops the most recent error message and returns nothing */
- void Yara_popLastError(); - -

Yara is designed to be as fast as possible, yet be usable and maintainable. Some of the choices for the parser and the renderer were made uniquely for speed: -

Yara uses the Expat XML parser, which is the fastest XML parser I know.
- Though Expat is neither a SAX nor a DOM parser, it suits its purpose exactly and is the de-facto standard for fast XML parsing.
Yara uses templates for rendering, in which it replaces tags with the contents of what it found in the RSS stream.
- To render an RSS stream, it searches in the template for tags that look like this: $$__tagname__$$. It then - uses a perfect hash, generated by GNU gperf, to look up the function to use to insert whatever the tag corresponds to, and inserts - whatever needs inserting.
- This means that this RSS renderer doesn't necessarily render RSS into HTML: you could, if you wanted, use it to generate C code that - statically contains the RSS feed.

Parsing is done in two steps: first, the RSS stream is parsed, then the template is used to generate a header, each item found in the stream, - and a footer. The template therefore consists of a template text for all three.

Yara will not download the stream for you: most RAD tools, frameworks, etc. come with easy-to-use methods to download files from the internet, - so I didn't see an immediate need to implement this.

Yara comes with an example application, which is a stand-alone RSS viewer written in Turbo C++. The viewer loads the parser/renderer DLL - dynamically, which is intended to demonstrate not only that the DLL can be compiled with a different C++ compiler, but that it can be used as - a plug-in for your applications.

Yara: Yet Another RSS Aggregator

Yara is a fast, embeddable RSS aggregator and parser. It is written in C++ and exposes a very simple API in C.
+ For the time being, the C API consists of the following functions:
+

+ /* returns 0 on success */
+ int Yara_render(
+     const char * target_filename /* name of the file to render into */,
+     const char * template_filename /* compiled template to use */,
+     const char * rss_xml /* RSS stream to parse and render */);
+
+ /* returns 0 on success */
+ int Yara_compileTemplate(
+     const char * target_filename /* name of the file to save the compiled template to */,
+     const char * header_filename /* name of the file with the header template */,
+     const char * footer_filename /* name of the file with the footer template */,
+     const char * item_filename /* name of the file with the item template */);
+
+ /* returns a pointer to the most recent error message */
+ const char * Yara_getLastError();
+
+ /* pops the most recent error message and returns nothing */
+ void Yara_popLastError(); +

Yara is designed to be as fast as possible, yet be usable and maintainable. Some of the choices for the parser and the renderer were made uniquely for speed: +

Yara uses the Expat XML parser, which is the fastest XML parser I know.
+ Though Expat is neither a SAX nor a DOM parser, it suits its purpose exactly and is the de-facto standard for fast XML parsing.

Yara uses templates for rendering, in which it replaces tags with the contents of what it found in the RSS stream.
+ To render an RSS stream, it searches in the template for tags that look like this: $$__tagname__$$. It then + uses a perfect hash, generated by GNU gperf, to look up the function to use to insert whatever the tag corresponds to, and inserts + whatever needs inserting.
+ This means that this RSS renderer doesn't necessarily render RSS into HTML: you could, if you wanted, use it to generate C code that + statically contains the RSS feed.

Parsing is done in two steps: first, the RSS stream is parsed, then the template is used to generate a header, each item found in the stream, + and a footer. The template therefore consists of a template text for all three.

Yara will not download the stream for you: most RAD tools, frameworks, etc. come with easy-to-use methods to download files from the internet, + so I didn't see an immediate need to implement this.

Yara comes with an example application, which is a stand-alone RSS viewer written in Turbo C++. The viewer loads the parser/renderer DLL + dynamically, which is intended to demonstrate not only that the DLL can be compiled with a different C++ compiler, but that it can be used as + a plug-in for your applications.