Before I start working in earnest with MODx, I’m working through the things I need figuring out the basics and doing some simple "proof of concept" things..
One thing that I want to do is to integrate some existing PHP scripts into it, but I have a mental block on how the variables work.
Here is the situation: outside MODx, I have two PHP programs "input.php" and "output.php" - the input.php script produces an HTML form that the user fills in, and then the values are passed as POST variables to "output.php". The "output.php" script looks up some values in a MySQL database and formats the output.
Now, I can certainly create a MODx page with the HTML form on it, and I can create a snippet that does the work of output.php - but what I can’t see is how to "connect them together" so that the variables that my form creates arrive at the snippet... what would I specify as the "target" for the form submission? If I specify the MODx page containing my snippet, then can the snippet access $_POST, and will it contain just "my" variables or will there be a whole pile of other variables to do with MODx.
I know I’m not expressing this well, but hopefully somebody can see what I’m getting at..
Thanks
Gordon
You can create the input.php as one snippet and output.php as one like you say and then put those in separate documents and in the input.php snippet form target set the document that has the output.php snippet running what then get’s the form data from $_POST..
I would do the input and output in one and same snippet though.. in the snippet, you could have if ($_POST[’submit’]) {..} check or something that checks if the form is submitted or not. If it’s not, it would output the form with current document as target [~[*id*]~].. and if it is, it would process the user inputted data and output any error messages (and the form in that case) or redirect to some success document or something..
"He can have a lollipop any time he wants to. That's what it means to be a programmer."
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As far as I have been able to figure out, it goes like this (more or less):
1. index.php initiates an "ob" (ob_start) object, and a new $modx object.
2. index.php calls calls $modx->executeParser()
3. parser gets site settings ($modx->config array, such as $modx->config[’site_name’])
4. parser checks site’s available status and outputs the unavailable page or message if site is unavailable. Done.
5. parser unpublishes/publishes all documents that need to be published/unpublished at this time.
6. parser determines from the URL request how to get the page to be parsed (site_start? alias? docID?) and works out the ID of the document it wants.
7. parser invokes the OnWebPageInit event at this point.
8. parser invokes the OnLogPageHit event, if track_visitors is set to 1.
9. parser checks cache, if page is cached loads the cache file into $modx->documentContent and invokes the OnLoadWebPageCache event, and jumps straight to the outputContent function without further parsing.
10. parser calls getDocument Object, which goes through various access checks, and loads the $modx->documentObject array (such as $modx->documentObject[’pagetitle’]). It also adds the TV tags from the document’s template to the documentObject.
11. parser determines if page is published, and if not, if the user has permissions to view unpublished documents.
12. parser determines if page is a "reference" (weblink) and quits with a redirect if it is.
13. parser gets the document’s template and sets the $modx->documentContent array to the template’s content.
14. parser invokes the OnLoadWebDocument event. (at this point you can see the template with all the MODx tags).
15. parser inserts metatags and keywords
16. parser sets $modx->documentOutput to documentContent (still only the template, no tags parsed yet) and records its length (to see if it needs another pass)
17. parser invokes the OnParseDocument event.
18. parser merges the document’s content into documentOutput (the [*content*] tag). As far as I can tell, TVs are also parsed and merged at this time.
19. parser merges site settings tags into documentOutput (such as [(site_name)] ) and calls parseDocumentSource with documentOutput as an argument.
20. parseDocumentSource merges chunk content into documentOutput (any MODx tags in the chunk are passed through unchanged for the next pass to deal with).
21 parseDocumentSource merges snippet output into documentOutput.
22 parseDocumentSource merges placeholders into documentOutput.
23 parseDocumentSource checks length of documentOutput, and if it has changed, runs it through parseDocumentSource again (up to maxParserPasses). When either the length doesn’t change, or maxParserPasses is reached, the documentOutput is returned to the parser.
24. parser inserts any javascript or css blocks (regClientStarupScript() ,etc)
25 parser sends documentOutput to outputContent function
26 outputContent deals with uncached snippet calls (coming from a cached document)
27 outputContent runs through parseDocumentSource again (to parse these uncached snippet calls)
28 outputContent deals with any more javascript or css blocks (in case the uncached snippet call had any)
29 outputContent gets rid of any unused placeholder tags
30 outputContent rewrites any URLs in the content
31 outputContent sets up content-type and content-disposition headers
32 outputContent sets up the timing, number of queries values ([^q^] etc)
33 outputContent invokes the OnWebPagePrerender event
34 outputContent echoes the final documentOutput. Well, not exactly, since the whole thing has been wrapped in an "ob" object. But that simple "echo $this->documentOutput;" does seem a little anticlimactic.
And interesting thing you can do is to set $modx->dumpSnippets to 1 (either edit the index.php file or make a plugin) for some debugging information.
yes, this should go definitely into the wiki, with maybe some code snipplets from the parser from some of the most interesting parts, like how tvs and chunks are merged and that snippets are evaled etc.. Great post!
"He can have a lollipop any time he wants to. That's what it means to be a programmer."
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Well, if somebody wants to put it in the wiki, be my guest. I’m not all that sure of some of the steps, especially exactly where the TVs get parsed. I hope if it does get put in the wiki somebody who knows more about it than I do can correct it.
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