Trying to combine defined templates with variables

[bunner_bob]

I have a class. In that class, at the top, I define a variable and assign it a string that contains some placeholder variables. Later in the class, I determine the values of those variables and combine them with the string. I'm doing it a really clunky way right now - there must be a better way. Something using references, perhaps?

This is how I'd like it to work. Of course it doesn't work, for obvious reasons...

var $lineitem;

function InitializeVars() {
    $this->lineitem = "<p class=\"smallverdana\">" . $name . "</p>";
}

function Foo() {
    $this->InitializeVars();
    $name = "Dave";
    echo $this->lineitem;
}

This is a VAAASTLY simplified example - actually I have many and more complicated formatted strings (setting up headers with colors, multiple parameters, etc.) It's not practical to call "InitializeVars()" after all the vars are set (though it may be the only way to do this). I'm just wondering if there is a way, using references or some clever function, to combine variables (after they're given a value) with a pre-defined string as that string is output, passed, read back, whatever.

The current way I'm doing it is to set my string up like this:

$this->lineitem = "<p class=\"smallverdana\"><!--NAME--></p>";

then copy values into a parameters array:

$this->parameters['NAME'] = "Dave";

and finally combine the parameters with the string thusly:

function ParmsToTemplate($string) {
    foreach ($this->parameters as $key => $value) {
        $template_name = '<!--' . $key . '-->';
        $string = str_replace($template_name, $value, $string);
    }
    return $string;
}

and then call it with

echo $this->ParmsToTemplate($this->lineitem);

The whole process just feels kind of ugly and spaghetti-ish when I look at my code. Though it works just fine. But there has to be a better way.

Any ideas?

• Bob

[AstroTeg]

I actually have a templete library based off of the ideas you posted. Although its not in a class. Its just a set of functions.

My parse function looks like this:

function ParseTemp($string, $ent, $null = '')
{
	while ($each_ent = each($ent))
		$string = str_replace("<!--$".$each_ent[0]."$-->", ((is_array($each_ent[1])) ? '' : $each_ent[1]), $string);

if($null == true)								// null out any stragglers
	$string = preg_replace("/<!--\\$[^ \\$]*?\\$-->/s", '', $string);

return $string;
}  // end function ParseTemp($string,$ent)

My parsing is based on an associative array containing the strings I want to swap into the template.

This function allows me to blindly pass an array (which could contain subarrays - it'll check for that instead of bombing out). I pass along the template as a string to work with. Then there's an additional parameter to clear out all variable tags in the template. This has been supper handy for clearing out any stragglers and has been handy for leaving them in for later processing.

As you may notice, I use <!--$ and $--> for my tags. This will cause MAJOR problems in Java (used <!--% and %--> instead). I went this route so I didn't accidentally pick off any HTML comments that one might sprinkle in the page. This is your library so I'll let you decide if this will be a problem or not.

As to your original question about the flow, classes make things a little sticky here. I really wish to make my template system a class, but I haven't figured out a good way of keeping track of the variable data.

The beauty of the associative array is $POST, $GET, and mysql_fetch_array() all return associative arrays which work awesome with my ParseTemp function.

The flow I use is: load the template from a file (I put all the HTML into a template which also contains the template variables <!--$[var name]$-->). Then I have my code do whatever it needs to. Then I load up the array I wish to use to populate the template. About 90% of the time, I'll be using $POST or $GET since a lot of the web deals with form data (and templating allows the user's data to be redisplayed pretty easily). When I'm all set, I just call the ParseTemp() function and echo the results. This, I think, is pretty close to what you had posted. It feels a little clunky at first, but it works. I'm not sure if having it all in a class is what it making it clunky. I'd love to see this in a class where it wasn't so clunky.

If you wish to see my template library, let me know (maybe via PM). It may or may not spark some ideas...

[bunner_bob]

I like your function, because it skips the step of having to say

$this->parameters['VALUE'] = $value;

Your function does it all in one step.

Otherwise, we both suffer the same when we have to change a value, rather than just feed it in directly from a GET or POST.

For instance, I have a couple of forms that pass along user-input dates (in normal human format) after which the dates are reformatted into Unix timestamps before doing something with them. Or vice versa. Lots of other things like that. In those cases I need to build my own array as I go - same for you of course, as I'm sure you're used to.

Maybe we've got it boiled down as far as it's gonna go...mmm, like syrup!

• Bob

[AstroTeg]

Dates are a rough animal, but they don't usually slow me down much.

// assume $get = $_GET;
	$stopdate = date('Y-m-d 13:59:59', strtotime(($get['rangestop_month'] + 1). '/' . $get['rangestop_day'] . '/' . $get['rangestop_year']));

The form has 3 drop downs - month, day, and year. I let strototime work its magic. And then I use the $stopdate (and associated $startdate if needed) in the query itself. In the above code, you can format the date to however you need it. And if someone manages to enter "Feb 31 2002" strtotime will still attempt to make sense of it.

As for re-populating these drop down boxes - that's where it gets tough. I build a JavaScript function which takes a field and a value and finds the match and then selects it (regardless of the data involved). Then I setup a series of function calls. Each call specifies the field and then I put in the associated template date variable. Problem solved!

I've been trying to figure out what you mean with the date situation, and I might clarify: I usually only do templating with HTML stuff. I haven't tried templating queries just because I haven't found the need (or maybe "discovered" the need).

Also, you ALWAYS want to validate your GET and POST data before you do any submitting to a database. I've got a system setup to validate after the submit. If the validation fails, pass a built up error message back. If there's a string, then there was an error and return back to the previous function (hard coded) with the post/get variables (beauty here is it repopulates). Toss the error message in either get or post and drop the error message variable into your template and you have the error automatically drop in for you. This has saved me a ton of time in setting up validation and then shuffling the user around to the proper HTML page.

As for changing a value, I don't normally run into this. I do do some tricks with building up a drop down box (via a function call) and it returns a string containing all the drop down box options in HTML format. It seems goofy at first, but works great (you can get fancy and pass the form value to this function and it'll know to select that item in the list).

[bunner_bob]

Yeah, I was templating my queries but it was a royal pain. I realized I didn't need to, as there wasn't any site specific stuff that had to be changed, other than table names, which could be set up as class variables ahead of time.

One typical situation I have is retrieving a set of results from a table and outputting it as a line item in a list. There might be a link, in which case I do a lookup of the "actual" URL based on an itemtype field in the retrieved row. Some links are more complex than others, since some itemtypes point at sub-pages within other pages (for instance, a job listing might be subordinate to the "contact us" page). In any case, usually some of the data in a line/template comes from a retrieved row, other data comes from some constant for the page, other data comes from a looked-up equivalent to something in the row.

If I was going to use your method, I'd probably want to build a new array using the retrieved/modified retrieved values, plus page constants, looked-up equivalents, etc. Which is what I'm doing already. I think your method still saves me a step - I'll have to give it a shot.

• bob

[AstroTeg]

Ah... I see what you're saying. You need to modify (maybe tweak is a better word) the database data for links and such in the HTML.

I see your problem. Been there, done that, wrote code around it. Twice. 🙂

I've built a CopyArray function since I didn't see PHP had something like this built in. While traversing each row, I might need to issue a 2nd query to the database and I let a function handle that. Ideally, I try to get it to just return 1 variable such as a string which I can add to my $row array (with the idea $row gets passed to ParseTemp). If I need to do some tricks, I'll do them in the while loop. I've gone so far with this method to actually split the template into parts - a header (including the data table definition), 1 section to be the column headers, 1 section for the data, then the footer. Works pretty well and allows things for easy updating.

More recenlty, I've had a need to produce HTML and CSV (Excel friendly) reports. I had to get creave to handle the special cases like you described (lookups, formatting, etc). I can safely say in this scenerio, I ditched templates and built a couple functions to handle producting 1 string/line of CSV/HTML.

In cases like this, I'd recommend thinking about it in simplest terms. You might find adding some joins to your query might make it all work. Or you might find adding a function to handle getting the extra data from within your record traversal to work for you.

[bunner_bob]

You know, now that I'm thinking about it, rather than having template lines that look like this

$this->templateline = "<p class=\"verdanasmall\"><a href=\"<!--LINKBASE-->?cat=<!--CAT-->&id=<!--ID-->\"><!--TITLE--><!--DATEEXTENSION--></a></p>";

I could format everything within and including the <a> tag more explicitly in PHP and just have my template say

$this->templateline = "<p class=\"verdanasmall\"><!--CONTENTS--></p>";

Then I'm truly separating form (the <p> tag, breaks, etc.) from function (links & such) which don't care what they look like.

Hmm....

[AstroTeg]

Its up to you. I'd go with the first method over the second UNLESS its uber painful to do the first method.

My approach and goal is to keep the HTML OUT of the PHP code. Anything I can do to do that makes life easier all around.

Whatever works for you, run with it. Just keep in mind what your goals are...