Modifying a Project

Make changes to a Mendix project file using the writer API. Always back up your .mpr file before modifying it.

Opening for Writing

writer, err := modelsdk.OpenForWriting("/path/to/MyApp.mpr")
if err != nil {
    panic(err)
}
defer writer.Close()

The writer provides access to the underlying reader via writer.Reader().

Complete Example

package main

import (
    "github.com/mendixlabs/mxcli"
)

func main() {
    // Open for writing
    writer, err := modelsdk.OpenForWriting("/path/to/MyApp.mpr")
    if err != nil {
        panic(err)
    }
    defer writer.Close()

    reader := writer.Reader()
    modules, _ := reader.ListModules()
    dm, _ := reader.GetDomainModel(modules[0].ID)

    // Create a new entity
    customer := modelsdk.NewEntity("Customer")
    writer.CreateEntity(dm.ID, customer)

    // Add attributes
    writer.AddAttribute(dm.ID, customer.ID, modelsdk.NewStringAttribute("Name", 200))
    writer.AddAttribute(dm.ID, customer.ID, modelsdk.NewStringAttribute("Email", 254))
    writer.AddAttribute(dm.ID, customer.ID, modelsdk.NewBooleanAttribute("IsActive"))
    writer.AddAttribute(dm.ID, customer.ID, modelsdk.NewDateTimeAttribute("CreatedDate", true))

    // Create another entity
    order := modelsdk.NewEntity("Order")
    writer.CreateEntity(dm.ID, order)

    // Create an association
    assoc := modelsdk.NewAssociation("Customer_Order", customer.ID, order.ID)
    writer.CreateAssociation(dm.ID, assoc)
}

Writer Methods

Modules

writer.CreateModule(module)
writer.UpdateModule(module)
writer.DeleteModule(id)

Entities

writer.CreateEntity(domainModelID, entity)
writer.UpdateEntity(domainModelID, entity)
writer.DeleteEntity(domainModelID, entityID)

Attributes

writer.AddAttribute(domainModelID, entityID, attribute)

Associations

writer.CreateAssociation(domainModelID, association)
writer.DeleteAssociation(domainModelID, associationID)

Microflows and Nanoflows

writer.CreateMicroflow(microflow)
writer.UpdateMicroflow(microflow)
writer.DeleteMicroflow(id)
writer.CreateNanoflow(nanoflow)
writer.UpdateNanoflow(nanoflow)
writer.DeleteNanoflow(id)

Pages and Layouts

writer.CreatePage(page)
writer.UpdatePage(page)
writer.DeletePage(id)
writer.CreateLayout(layout)
writer.UpdateLayout(layout)
writer.DeleteLayout(id)

Other

writer.CreateEnumeration(enumeration)
writer.CreateConstant(constant)

Helper Functions

// Create attributes
modelsdk.NewStringAttribute(name, length)
modelsdk.NewIntegerAttribute(name)
modelsdk.NewDecimalAttribute(name)
modelsdk.NewBooleanAttribute(name)
modelsdk.NewDateTimeAttribute(name, localize)
modelsdk.NewEnumerationAttribute(name, enumID)

// Create entities
modelsdk.NewEntity(name)                 // Persistable entity
modelsdk.NewNonPersistableEntity(name)   // Non-persistable entity

// Create associations
modelsdk.NewAssociation(name, parentID, childID)      // Reference (1:N)
modelsdk.NewReferenceSetAssociation(name, p, c)       // Reference set (M:N)

// Create flows
modelsdk.NewMicroflow(name)
modelsdk.NewNanoflow(name)

// Create pages
modelsdk.NewPage(name)

// Generate IDs
modelsdk.GenerateID()

Data Flow

sequenceDiagram
    participant App
    participant SDK as modelsdk
    participant Writer
    participant FS as File System

    App->>SDK: OpenForWriting("project.mpr")
    SDK->>Writer: NewWriter(path)
    Writer->>FS: Load existing units
    SDK-->>App: Writer

    App->>SDK: NewEntity()
    SDK-->>App: *Entity

    App->>SDK: AddEntity(dm, entity)
    SDK->>Writer: SerializeEntity(entity)
    Writer->>Writer: Generate BSON

    App->>SDK: Save()
    SDK->>Writer: Write all modified units
    Writer->>FS: Write .mxunit files
    Writer->>FS: Update .mpr metadata

Running the Example

cd examples/modify_project
go run main.go /path/to/MyApp.mpr

Warning: Always backup your .mpr file before modifying it.