Nested Model HTTP request failing on init

[stuartwk]

Hey folks, I'm just getting started with Bubble Tea.
I created a really simple project, which makes an HTTP call, and displays a list based on what is returned: https://github.com/stuartwk/nested_model_troubleshooting. This works fine.

I want to build it out a bit more, so I tried moving the code into a sub model. But the HTTP request isn't working once I moved the code into a sub model. Exact same fetch function, just moved. Returns a statuscode of 0. No data returned or rendered. https://github.com/stuartwk/nested_model_troubleshooting/tree/pools-package

I feel like I'm making a noob mistake and missing something simple. Any ideas why this code works if everything is in the main model, but when I move it into a sub model, it fails? Thanks in advance!

[stuartwk]

Adding some code snippets to get help on this.
In the main branch, when everything is inside main.go, the HTTP request works.

package main

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"os"

	tea "github.com/charmbracelet/bubbletea"
)

const url = "https://midgard.ninerealms.com/v2/pools"

type errMsg struct{ error }

func (e errMsg) Error() string { return e.error.Error() }

type poolsMsg struct {
	pools []Pool
}

type Pool struct {
	Asset string `json:"asset"`
}

type model struct {
	pools  []Pool
	Err    error
	cursor int
}

func (m model) Init() tea.Cmd {
	return fetchPools
}

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case poolsMsg:
		m.pools = msg.pools
	case errMsg:
		m.Err = msg
		return m, nil
	case tea.KeyMsg:
		switch msg.String() {
		case "q":
			return m, tea.Quit
		case "j", "down":
			m.cursor++
			if m.cursor >= len(m.pools) {
				m.cursor = 0
			}
			return m, nil
		case "k", "up":
			m.cursor--
			if m.cursor < 0 {
				m.cursor = len(m.pools) - 1
			}
			return m, nil
		}
	}

	return m, nil
}

func (m model) View() string {
	s := fmt.Sprintf("Checking %s...\n", url)
	if m.Err != nil {
		s += fmt.Sprintf("something went wrong: %s", m.Err)
	} else {

		s += fmt.Sprintf("Found %d pools\n", len(m.pools))

		for i, pool := range m.pools {

			cursor := " " // no cursor
			if m.cursor == i {
				cursor = ">" // cursor!
			}

			s += fmt.Sprintf("%s %s\n", cursor, pool.Asset)
		}

	}

	return s + "\n"
}

func main() {
	p := tea.NewProgram(model{})
	if _, err := p.Run(); err != nil {
		fmt.Printf("Alas, there's been an error: %v", err)
		os.Exit(1)
	}
}

func fetchPools() tea.Msg {
	resp, err := http.Get("https://midgard.ninerealms.com/v2/pools")
	if err != nil {
		return errMsg{err}
	}

	defer resp.Body.Close()

	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return errMsg{err}
	}

	var pools []Pool
	err = json.Unmarshal(data, &pools)
	if err != nil {
		return errMsg{err}
	}

	return poolsMsg{pools}

}

But when I separate things into their own packages, something is going wrong with the HTTP request when it is inside of a nested model.

// main.go
package main

import (
	"fmt"
	"os"

	"github.com/stuartwk/http_troubleshooting/pools"

	tea "github.com/charmbracelet/bubbletea"
)

type sessionState int

const (
	poolsView sessionState = iota
	poolView
)

type model struct {
	state      sessionState
	poolsModel pools.Model
}

func (m model) Init() tea.Cmd {
	return nil
}

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	var cmd tea.Cmd
	var cmds []tea.Cmd
	switch msg := msg.(type) {
	case tea.KeyMsg:
		switch msg.String() {
		case "q", "ctrl+c", "esc":
			return m, tea.Quit
		}
	}

	switch m.state {
	case poolsView:
		newPool, newCmd := m.poolsModel.Update(msg)
		poolModel, ok := newPool.(pools.Model)
		if !ok {
			panic("could not asset pools.Model")
		}
		m.poolsModel = poolModel
		cmd = newCmd
	default:
		return m, nil
	}

	cmds = append(cmds, cmd)

	return m, tea.Batch(cmds...)
}

func (m model) View() string {
	switch m.state {
	case poolsView:
		return m.poolsModel.View()
	default:
		return m.poolsModel.View()
	}
}

func main() {
	p := tea.NewProgram(model{})
	if _, err := p.Run(); err != nil {
		fmt.Printf("Alas, there's been an error: %v", err)
		os.Exit(1)
	}
}

// pools/pools.go
package pools

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"

	tea "github.com/charmbracelet/bubbletea"
)

const url = "https://midgard.ninerealms.com/v2/pools"

type errMsg struct{ error }

func (e errMsg) Error() string { return e.error.Error() }

type poolsMsg []Pool

type Pool struct {
	Asset string `json:"asset"`
}

type Model struct {
	pools  []Pool
	Err    error
	cursor int
}

func (m Model) Init() tea.Cmd {
	return fetchPools
}

func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case poolsMsg:
		m.pools = msg
		return m, nil
	case errMsg:
		m.Err = msg
		return m, nil
	case tea.KeyMsg:
		switch msg.String() {
		case "j", "down":
			m.cursor++
			if m.cursor >= len(m.pools) {
				m.cursor = 0
			}
			return m, nil
		case "k", "up":
			m.cursor--
			if m.cursor < 0 {
				m.cursor = len(m.pools) - 1
			}
			return m, nil
		}
	}

	return m, nil
}

func (m Model) View() string {
	s := fmt.Sprintf("Fetching %s...\n", url)
	if m.Err != nil {
		s += fmt.Sprintf("something went wrong: %s", m.Err)
	} else {

		// log the number of pools there are
		s += fmt.Sprintf("Found %d pools\n", len(m.pools))

		for i, pool := range m.pools {

			cursor := " " // no cursor
			if m.cursor == i {
				cursor = ">" // cursor!
			}

			s += fmt.Sprintf("%s %s\n", cursor, pool.Asset)
		}

	}

	return s + "\n"
}

func fetchPools() tea.Msg {
	resp, err := http.Get("https://midgard.ninerealms.com/v2/pools")
	if err != nil {
		return errMsg{err}
	}

	defer resp.Body.Close()

	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return errMsg{err}
	}

	var pools []Pool
	err = json.Unmarshal(data, &pools)
	if err != nil {
		return errMsg{err}
	}

	return poolsMsg(pools)

}

Basically, fetchPools works if it's in not nested, but breaks when it is nested in a sub model. Any help appreciated!