AzureRecipes

Introduction

Especially for integration scenarios there is often the need to provide a simple configuration for mappings. This may include property mappings but also routing configurations (“if this value, then that service”). This snippet provides a simple base class to define such mappings with easy editable JSON configurations, typically stored in a Blob Storage. It supports complex requirements such as resolution based on multiple criterias, wildcard support and fallback / default mechanism.

The snippet demonstrates a usage in an Azure Function, but it can be easily used in any C# code without any dependencies other than Newtonsoft JSON.

Getting Started

Create mapping configurations like this (demo-content-type-mapping):

{
    "Image:psd": "PSD",
    "Image:*": "PHOTO",
    "Movie:*": "VIDEO",
    "*:pdf": "PDF",
    "MS PowerPoint:*": "PRESENTATION",
    "MS Excel:*": "EXCEL",
    "MS Word:doc": "DOC",
    "MS Word:docx": "DOCX",
	"*": "OTHER"
}

Features:

• Multiple criterias which are resolved. These are separated with ‘:’ and are not limited
• Wildcard support with ‘*’ (matches any number of characters)
• Order of definitions is relevant, only the first match is resolved. This way you can define default / fallback values at the end
• Supports any value type which can be deserialized by Newtonsoft JSON. The sample above shows the usage with string values, but you can also define mappings for e.g. integers like "*:pdf": 42. All values have to be of same type

You can then parse and use this file in any place like:

Mapping<string> contentTypeMapping = Mapping<string>.CreateFromFileContent(mappingFileContent);

string contentType = contentTypeMapping.GetMatchOrDefault("Movie", "mp4"); // Returns VIDEO

The main class is Mapping

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