Sure, here is a Flutter function that takes the contents of an HTML file as a string, finds standard HTML includes, and replaces them with the contents of the corresponding files from a "snippets" folder.
To achieve this, you'll need to use Dart's RegExp
to find the includes and the dart:io
library to read the contents of the snippet files.
Here's the implementation:
import 'dart:io';
import 'dart:async';
Future<String> replaceIncludes(String htmlContent) async {
// Define a regular expression to find includes like <!--#include file="filename.html"-->
final includeRegex = RegExp(r'<!--#include file="(.+?)"-->');
// Find all matches in the HTML content
final matches = includeRegex.allMatches(htmlContent);
// Iterate over all matches
for (final match in matches) {
// Extract the filename from the match
final filename = match.group(1);
if (filename != null) {
// Construct the path to the snippet file
final snippetPath = 'snippets/$filename';
// Read the contents of the snippet file
try {
final snippetContent = await File(snippetPath).readAsString();
// Replace the include directive with the contents of the snippet file
htmlContent = htmlContent.replaceFirst(match.group(0)!, snippetContent);
} catch (e) {
print('Error reading file $snippetPath: $e');
// Handle the error as needed
}
}
}
return htmlContent;
}
void main() async {
// Example usage
final htmlFileContent = '''
<html>
<head>
<!--#include file="header.html"-->
</head>
<body>
<h1>Welcome</h1>
<!--#include file="footer.html"-->
</body>
</html>
''';
final updatedHtmlContent = await replaceIncludes(htmlFileContent);
print(updatedHtmlContent);
}
- Regular Expression: The
includeRegex
is a regular expression that matches the<!--#include file="filename.html"-->
pattern. - Finding Matches:
allMatches
method is used to find all occurrences of the include directives in the HTML content. - Iterating over Matches: For each match, the filename is extracted and the corresponding snippet file is read.
- Replacing Includes: The
replaceFirst
method replaces the include directive with the contents of the snippet file. - Error Handling: If there is an error reading a file, it is caught and logged, allowing the function to continue processing other includes.
- Ensure the
snippets
folder is in the correct location relative to your project directory. - This function assumes the snippets are small and can be read synchronously. For large files or a large number of includes, consider optimizing the reading and processing.
You can use this function to process HTML files and replace includes as needed.