go-fastreport: FastReport .NET, ported to pure Go

What is go-fastreport?

go-fastreport ports FastReport .NET Open Source's reporting model to Go: bands, objects, an expression language, and FRX serialization, plus data binding and export. The usual workflow is to design a report visually in FastReport .NET, save it as an .frx file, then load and run that same template from a Go program — no .NET runtime required at run time.

It is pure Go with no CGo dependencies, so it cross-compiles and runs anywhere Go does. The engine has been smoke tested against 50+ real FastReport .frx sample files.

• Open source
• MIT licensed
• Pure Go
• No CGo
• Go 1.23+
• Free

Features

Quick start

Requires Go 1.23+.

go get github.com/andrewloable/go-fastreport

The common workflow: design a report in FastReport .NET, save it as an .frx file, then load it at runtime and bind a JSON data source.

r := reportpkg.NewReport()
r.Load("report.frx")

// Register parameters and a JSON data source keyed by alias.
// The engine resolves DataBand.DataSource="employees" to this
// source automatically, matching how FastReport .NET wires data.
ds := jsondata.New("employees")
ds.SetJSON(employeeJSON)
ds.Init()

dict := r.Dictionary()
dict.AddParameter(&data.Parameter{Name: "ReportTitle", Value: "Employee Directory"})
dict.AddDataSource(ds)

e := engine.New(r)
e.Run(engine.DefaultRunOptions())

exp := html.NewExporter()
exp.Title = r.Info.Name
exp.Export(e.PreparedPages(), os.Stdout)

A complete, runnable version lives in examples/frx_json. Other examples cover building a report entirely in code and using each data source standalone.

Data sources

All four data source types embed data.BaseDataSource and satisfy band.DataSource directly — no adapter wrapper needed. Register one in the report Dictionary for FRX workflows, or assign it straight to a DataBand when building a report in code.

JSON

ds := jsondata.New("customers")
ds.SetJSON(`[{"Name":"Alice","Age":30},{"Name":"Bob","Age":25}]`)
ds.Init()

XML

ds := xmldata.New("orders")
ds.SetXML(`<Orders><Item Product="Apple" Qty="5"/></Orders>`)
ds.Init()

CSV

ds := csvdata.New("sales")
ds.SetFilePath("sales.csv")
ds.HasHeader = true
ds.Init()

SQL

db, _ := sql.Open("postgres", "...")
ds := sqlds.New("employees", db,
    "SELECT id, name FROM employees WHERE active = $1", true)
ds.Init()

Export

HTML, PDF, and PNG exporters share the same shape — construct, set options, call Export with the prepared pages and a writer.

// HTML
exp := html.NewExporter()
exp.Title = "My Report"
exp.EmbedCSS = true
exp.Export(preparedPages, &buf)

// PDF (structural)
exp := pdf.NewExporter()
exp.Export(preparedPages, outputWriter)

// PNG, 2x scale for high-DPI
exp := image.NewExporter()
exp.Scale = 2.0
exp.Export(preparedPages, outputWriter)

// Page range on any exporter
exp.PageRange = export.PageRangeCustom
exp.PageNumbers = "1,3-5"

Package overview

Band types

Status & roadmap

This is an active port of FastReport .NET Open Source. Functional today:

• Core engine: data iteration, band rendering, page breaks, multi-column layouts, groups
• Data binding: JSON, XML, CSV, SQL, and custom in-memory data sources
• Dictionary-based DataSource resolution, matching the FastReport .NET model
• FRX serialization: read and write .frx files, including real FastReport sample files
• Export: HTML, PDF (structural), PNG image
• Aggregate totals: Sum, Count, Average, Min, Max with per-group reset
• CanGrow / CanShrink dynamic band height, and [bracket] expression evaluation
• Conditional formatting: HighlightCondition evaluation (Fill, TextColor, Font, Visible), first-match-wins
• Master-detail relation traversal at engine runtime, filtering child data sources per parent row
• FRX gzip compression: transparent read and write of compressed .frx files
• HTML export of images and vector shapes (Shape, Line, PolyLine, Polygon, CheckBox)

See porting-plan.md for the detailed, dated roadmap of what's landed.