Jam.py documentation

Server-side report programmingΒΆ

When a server gets a request from a client to generate report, it first of all creates a copy of the report and then this copy calls the generate method.

This method triggers the on_before_generate event. In this event handler developer should write a code that generates the content of the report.

For example for the invoice report of the Demo application this event is as follows:

def on_generate(report):
    invoices = report.task.invoices.copy()

    customer = invoices.firstname.display_text + ' ' + invoices.customer.display_text
    address = invoices.billing_address.display_text
    city = invoices.billing_city.display_text + ' ' + invoices.billing_state.display_text + ' ' + \
    date = invoices.invoicedate.display_text
    shipped = invoices.billing_address.display_text + ' ' + invoices.billing_city.display_text + ' ' + \
        invoices.billing_state.display_text + ' ' + invoices.billing_country.display_text
    taxrate = invoices.taxrate.display_text
    report.print_band('title', locals())

    tracks = invoices.invoice_table
    for t in tracks:
        quantity = t.quantity.display_text
        track = t.track.display_text
        unitprice = t.unitprice.display_text
        sum = t.amount.display_text
        report.print_band('detail', locals())

    subtotal = invoices.subtotal.display_text
    tax = invoices.tax.display_text
    total = invoices.total.display_text
    report.print_band('summary', locals())

First, we use the copy method to create a copy of the invoices journal.

invoices = report.task.invoices.copy()

We create the copiy because multiple users can simultaneously generate the same report in parallel threads.

Then we call the set_where method of the copy:


where report.id.value is report id parameter, the value of which we set in the on_before_print_report event handler on the client and which is equal to the current id field value of the invoice journal.

Then, using the open method, we obtain the records on the server. After that the print_band method is used to print title band:

report.print_band('title', locals())

But before that we assign values to four local variables: customer, address, city and date that correspond to programmable cells in the title band in the report template.

Then the same way we generate detail and summary bands.

When the report is generated and the value of report extension attribute, set on the client, is not equals ‘pdf’ the server converts the ods file using LibreOffice.

Once the report is generated it is stored in a report folder of the static directory and the server sends the client the report file url.