[Custom Block] How to access the value between start and end of the block?

[dehghani-mehdi]

For example:

{% foo %}
Hello
{% endfoo%}

parser.RegisterEmptyBlock("foo", (statements, writer, encoder, context) =>
{
    // how to access the value `Hello` here?
});

[hishamco]

Try

return statements.RenderStatementsAsync(writer, encoder, context);

[dehghani-mehdi]

I want to access Hello inside RegisterEmptyBlock, I tried var result = statements.RenderStatementsAsync(writer, encoder, context); but that doesn't give me the Hello

[hishamco]

Seems the above code will give you the result after rendering

[hishamco]

Is the result equal to hello there?

It depends, if your block does nothing the code below should work

if not, you don't know what I am talking about, so please stop posting irrelevant comments

I know what I'm talking about, so be kind when you write your comments, what I mean in my comment is the code will return the result after rendering

parser.RegisterEmptyBlock("hello", static (writer, encoder, context) =>
{
    return s.RenderStatementsAsync(writer, encoder, context);
});

var template = parser.Parse("{% foo %} hello {%- endfoo %}");
var result = template.Render();

The result should be Hello

[hishamco]

Please elaborate on what you are trying to do to avoid misunderstanding your question

[sebastienros]

Here is an example on how to use it. the block can contain "statements" that need to be processed. In your example it's a single Text Statement, but it could be another block, loops, ... You just need to process them all in order. Or evaluate them in a buffer and do something interesting with them.

fluid/Fluid.Tests/Extensibility/ExtensibilityTests.cs

Lines 62 to 77 in 8564be1

	[Fact]
	public void ShouldRenderEmptyBlocks()
	{
	var parser = new CustomParser();
	parser.RegisterEmptyBlock("hello", static (s, w, e, c) =>
	{
	w.Write("Hello World");
	return s.RenderStatementsAsync(w, e, c);
	});
	var template = parser.Parse("{% hello %} hi {%- endhello %}");
	var result = template.Render();
	Assert.Equal("Hello World hi", result);
	}

[dehghani-mehdi]

@sebastienros I saw that, actually I checked all test cases before posting the question here. that doesn't help me. you wrote a hard-coded value, Hello World to the output, but I need to access the hi part parser.RegisterEmptyBlock("hello", static (s, w, e, c) => { >>> HERE <<< });, do something with it, then write the result to output, how can I do that?

[sebastienros]

Assert.Equal("Hello World hi", result);

Can you see the "hi" here? Meaning it's written to the output, by this:

s.RenderStatementsAsync(w, e, c)

w is the "output text writer" so this code outputs anything from the withing the block ("hi") to the same source writer. If you want to intercept it, create a custom TextWriter, write it there, do something with the string then write the result to w.

[dehghani-mehdi]

I don't know why you didn't mention it, but the answer was writer.ToString();

parser.RegisterEmptyBlock("foo", (statements, writer, encoder, context) =>
{
    statements.RenderStatementsAsync(writer, encoder, context)
    var result = writer.ToString(); // result here is the value `Hello`
    // manipulate result
    writer.Write(result);
    return Statement.Normal();
});

Thank you for the help.

[sebastienros]

No, this won't work as-is. You need to create a new Text Writer or you will get the results from everything else that was written from previous tags too.

create a custom TextWriter

[dehghani-mehdi]

You are right, I used the following code:

_parser.RegisterEmptyBlock("foo", static (statements, writer, encoder, context) =>
{
	using (var sw = new StringWriter())
	{
		statements.RenderStatementsAsync(sw, encoder, context);
                var result = sw.ToString();
                // manipulate result
                writer.Write(result);
	}

	return Statement.Normal();
});