![]() WatermarkFile, _, err := request. It's going to be pretty uncomplicated, just having the following structure:įunc (code *simpleQRCode) GenerateWithWatermark(watermark byte) (byte, error) The first thing to do is to create the project directory. This will be a PNG image that will be overlaid over the centre of the generated QR code. package main import ( 'fmt' 'net/url' ) func. Having had a squint at the source code I think it does a very good and standards compliant job. It doesnt break out the individual encoding functions for the parts of the URL, you have to let it construct the whole URL. the field is empty and its tag specifies the 'omitempty' option. The Go language is small, compiles really fast, and as a result it lets your mind focus on the actual problem and less on the tool you are using to solve it. You can do all the URL encoding you want with the net/url module. Each exported struct field is encoded as a Header field unless. Header expects to be passed a struct, and traverses it recursively using the following encoding rules. For the sake of simplicity, the tutorial will use a URL, but you could use almost anything, so long as it's less than 7,089 charactersĪn optional, third, parameter ( watermark) will also be supported in the later version of the code. Header, error) Header returns the http.Header encoding of v. content: This is a string that provides the QR code's content.size: This is an integer that sets the width and height of the QR code.Requests to the endpoint will require at least two POST request parameters: The application will be a simplistic web service with one endpoint ( /generate) that supports POST requests. Unfortunately most HTTP/2 is sent over TLS which means that, by default, Wireshark will not be able to decrypt the packets to be able to get to the HTTP/2 for decoding. A smartphone with a QR code scanner (which most of them should have, these days)īefore we dive in and start writing Go code, here's what the code will do. The popular Wireshark packet analyzer added decoding on HTTP/2 in version 1.12.0 and fully decodes HTTP/2 frames.My recommendation is Visual Studio Code with the Go extension Go (a recent version, or the latest, 1.20.5).To follow along with the tutorial, you don't need much, just the following things: Specifically, you're going to learn how to generate a plain one as well as one with an overlaid image, helpful if you want to add some organisational branding. So in this tutorial, you're going to learn how to generate them using Go. With that kind of variety and functionality, what's not to love about them?! They're used for a diverse range of tasks, such as providing information about bus routes and schedules, train journey information, sharing business card data, taking surveys, and paying for meals. Here's an example of one from City Square Mall in Singapore. The required data is then extracted from patterns that are present in both horizontal and vertical components of the image. Quoting Wikipedia: A QR code consists of black squares arranged in a square grid on a white background, including some fiducial markers, which can be read by an imaging device such as a camera, and processed using Reed–Solomon error correction until the image can be appropriately interpreted. QR, or Quick Response, codes were invented in 1994 in Japan.
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