QR code formats
Snabble supports online payments as well as transmission of a shopping cart to the retailer's cash desk. For this transmission, the following QR code formats are supported out of the box.
1. Snabble encoded cart
All scanned codes are written into one QR code in a CSV-style (semicolon-separated) format. Each line consists of a quantity and the scanned code of the product, and a header line allows easy detection of this format. For example, one Duplo (40084015) and two glasses of Nutella (4008400401621) would be encoded as e.g.:
snabble;1;1;2c4d2f9e-06c6-11ea-a9eb-4fcb432c057b
1;40084015
2;4008400401621
By default, lines are separated by a single newline character \n.
The first line is a special header line, containing metadata. It always starts with the character sequence snabble;, followed by two integer values, N and M. The value M specifies the total number of QR codes that need to be scanned by the cash register to read the complete purchase, in case it does not fit into a single code. The value N specifies the number of this QR code within the series of codes. For example, a single QR code will start with the header line snabble;1;1, and two codes would have the headers snabble;1;2 and snabble;2;2, respectively.
The fourth field of the header line is optional. If it is present, it contains the ID of the checkout process in the Snabble backend. After processing the transaction, the POS should update the state of the checkout process in the Snabble backend using this ID and the POS Integration API. If the checkout ID is empty or missing, the Snabble user may have processed the shopping trip without internet connection and the POS does not need to notify the Snabble backend after payment.
In future versions of this code, there may be additional fields in both the header line as well as the article lines. A POS implementation must therefore not rely on the exact number of fields.
For each project on the Snabble platform, a different set of delimiters and other parameters for the QR code can be configured. The available formatting parameters for this encoding are:
| Name | Default | Description |
|---|---|---|
| maxCodes | 100 | Maximum number of lines to fit into a single QR code. |
| separator | "\n" | The line separator. |
2. QrCodePOS
With this format, the QR code just contains the ID of the checkout process. The cash register is then able to fetch the shopping cart from the Snabble POS service, using this ID. The API for communication with the POS service is documented here:
3. Repetitions of scanned codes
With this encoding, all scanned codes are written into one QR code as if they were scanned one-by-one. By default, the scanned codes are separated by a newline character, so the code contains the codes line by line.
Example: One Duplo (40084015) and two glasses of Nutella (4008400401621).
With default formating:
0000040084015
4008400401621
4008400401621
For each project on the Snabble platform, a different set of delimiters and other parameters for the QR code can be configured. The available formatting parameters for this encoding are:
| Name | Default | Description |
|---|---|---|
| prefix | "" | The string at the beginning of the QR code. |
| separator | "\n" | The separator string between two scanned codes. |
| suffix | "" | A string at the end of the QR code. |
| maxCodes | 100 | Maximum number of codes to fit into a single QR code. |
The above example with prefix and delimiter: "XE" and suffix: "XZ" will result in the following code:
XE0000040084015XE4008400401621XE4008400401621XZ
