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https://github.com/adhocteam/pushup

Pushup is for making modern, page-oriented web apps in Go
https://github.com/adhocteam/pushup

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Pushup is for making modern, page-oriented web apps in Go

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# Pushup - a page-oriented web framework for Go



![workflow status](https://github.com/adhocteam/pushup/actions/workflows/go.yml/badge.svg)

[![Contributor Covenant](https://img.shields.io/badge/Contributor%20Covenant-2.1-4baaaa.svg)](CODE_OF_CONDUCT.md)



## Project status



Pushup is an experiment. In terms of the development life cycle, it should be considered **preview** pre-release software: it is largely functional, likely has significant bugs (including potential for data loss) and/or subpar performance, but is suitable for demos and testing. It has a decent unit test suite, including fuzzing test cases for the parser. Don't count on it for anything serious yet, and expect significant breaking changes. 



![screenshot of syntax highlighting of an example Pushup page](./example-syntax-highlighting.png)



-   [Pushup - a page-oriented web framework for Go](#pushup---a-page-oriented-web-framework-for-go)

    -   [What is Pushup?](#what-is-pushup)

        -   [Pages in Pushup](#pages-in-pushup)

    -   [Quick start with Docker](#quick-start-with-docker)

    -   [Getting started](#getting-started)

        -   [Installing Pushup](#installing-pushup)

            -   [Prerequisites](#prerequisites)

            -   [Install an official release](#install-an-official-release)

            -   [Install via Nix](#install-via-nix)

            -   [Install via git](#install-via-git)

            -   [Install via `go install`](#install-via-go-install)

        -   [Creating a new Pushup project](#creating-a-new-pushup-project)

    -   [Example demo app](#example-demo-app)

    -   [Go modules and Pushup projects](#go-modules-and-pushup-projects)

    -   [Project directory structure](#project-directory-structure)

    -   [Pages](#pages)

    -   [Layouts](#layouts)

    -   [Static media](#static-media)

    -   [File-based routing](#file-based-routing)

        -   [Dynamic routes](#dynamic-routes)

    -   [Enhanced hypertext](#enhanced-hypertext)

        -   [Inline partials](#inline-partials)

    -   [Basic web framework functionality](#basic-web-framework-functionality)

        -   [Escaping](#escaping)

    -   [Pushup syntax](#pushup-syntax)

        -   [How it works](#how-it-works)

        -   [Directives](#directives)

            -   [`^import`](#import)

            -   [`^layout`](#layout)

                -   [`^layout !` - no layout](#layout----no-layout)

        -   [Go code blocks](#go-code-blocks)

            -   [`^{`](#)

            -   [`^handler`](#handler)

        -   [Control flow statements](#control-flow-statements)

            -   [`^if`](#if)

            -   [`^for`](#for)

        -   [Expressions](#expressions)

            -   [Simple expressions](#simple-expressions)

            -   [Explicit expressions](#explicit-expressions)

        -   [Layout and templates](#layout-and-templates)

            -   [`^section`](#section)

            -   [`^partial`](#partial)

    -   [Vim syntax file](#vim-syntax-file)



Pushup is an experimental new project that is exploring the viability of a new

approach to web frameworks in Go.



Pushup seeks to make building page-oriented, server-side web apps using Go

easy. It embraces the server, while acknowledging the reality of modern web

apps and their improvements to UI interactivity over previous generations.



## What is Pushup?



Pushup is a program that compiles projects developed with the Pushup markup

language into standalone web app servers.



There are three main aspects to Pushup:



1. An opinionated project/app directory structure that enables **file-based

   routing**,

1. A **lightweight markup** alternative to traditional web framework templates

   that combines Go code for control flow and imperative, view-controller-like

   code with HTML markup, and

1. A **compiler** that parses that markup and generates pure Go code,

   building standalone web apps on top of the Go stdlib `net/http` package.



### Pages in Pushup



The core object in Pushup is the "page": a file with the `.up` extension that

is a mix of HTML, Go code, and a lightweight markup language that glues them

together. Pushup pages participate in URL routing by virtue of their path in

the filesystem. Pushup pages are compiled into pure Go which is then built

along with a thin runtime into a standalone web app server (which is all

`net/http` under the hood).



The main proposition motivating Pushup is that the page is the right level of

abstraction for most kinds of server-side web apps.



The syntax of the Pushup markup language looks like this:



```pushup



^import "time"



^{

    title := "Hello, from Pushup!"

}



^title



The time is now ^time.Now().String().



^if time.Now().Weekday() == time.Friday {

    
It's Friday! Enjoy the start to your weekend.


} ^else {

    
Have a great day, we're glad you're here.


}



```



You would then place this code in a file somewhere in your `app/pages`

directory, like `hello.up`. The `.up` extension is important and tells

the compiler that it is a Pushup page. Once you build and run your Pushup app,

that page is automatically mapped to the URL path `/hello`.



## Quick start with Docker



```shell

git clone https://github.com/adhocteam/pushup.git

cd pushup

make build-docker

```



Then create a scaffolded new project in the current directory:



```shell

docker run --rm -v $(pwd):/usr/src/app --user $(id -u):$(id -g) pushup new myproject

cd myproject

docker run --rm -v $(pwd):/usr/src/app --user $(id -u):$(id -g) -p 8080:8080 pushup run

```



See [Creating a new Pushup project](#creating-a-new-pushup-project) for more information.



## Getting started



To make a new Pushup app, first install the main Pushup executable.



### Installing Pushup



#### Prerequisites



-   go 1.18 or later



Make sure the directory where the go tool installs executables is in your

`$PATH`. It is `$(go env GOPATH)/bin`. You can check if this is the case with:



```shell

echo $PATH | grep $(go env GOPATH)/bin > /dev/null && echo yes || echo no

```



#### Install an official release



Download Pushup for your platform from [the releases page](https://github.com/adhocteam/pushup/releases).



#### Install via Nix



Pushup is available via the [Nix](https://nixos.org/) package manager. It is

currently in the [`unstable` channel](https://search.nixos.org/packages?channel=unstable&query=pushup).



* **Add to your local profile**



```shell

$ nix-env -iA nixpkgs.pushup

```



* **Create a temporary shell**



```shell

$ nix-shell -p pushup

```



* **Create a temporary shell (flakes)**



```shell

$ nix shell nixpkgs#pushup

```



* **Run Pushup without installing (flakes)**



```shell

$ nix run nixpkgs#pushup

````



#### Install via git



```shell

git clone [email protected]:AdHocRandD/pushup.git

cd pushup

make

```



#### Install via `go install`



Make sure you have Go installed (at least version 1.18), and type:



```shell

go install github.com/adhocteam/pushup@latest

```



### Creating a new Pushup project



To create a new Pushup project, use the `pushup new` command.



```shell

pushup new

```



Without any additional arguments, it will attempt to create a scaffolded new

project in the current directory. However, the directory must be completely

empty, or the command will abort. To simulataneously make a new directory

and generate a scaffolded project, pass a relative path as argument:



```shell

pushup new myproject

```



The scaffolded new project directory consists of a directory structure for

.up files and auxiliary project Go code, and a go.mod file.



Change to the new project directory if necessary, then do a `pushup run`,

which compiles the Pushup project to Go code, builds the app, and starts up

the server.



```shell

pushup run

```



If all goes well, you should see a message on the terminal that the Pushup app

is running and listening on a port:



```

↑↑ Pushup ready and listening on 0.0.0.0:8080 ↑↑

```



By default it listens on port 8080, but with the `-port` or `-unix-socket`

flags you can pick your own listener.



Open [http://localhost:8080/](http://localhost:8080/) in your browser to see

the default layout and a welcome index page.



## Example demo app



See the [example](./example) directory for a demo Pushup app that demonstrates

many of the concepts in Pushup and implements a few small common patterns like

some HTMX examples and a simple CRUD app.



Click on "view source" at the bottom of any page in the example app to see the

source of the .up page for that route, including the source of the "view

source" .up page itself. This is a good way to see how to write Pushup

syntax.



## Go modules and Pushup projects



Pushup treats projects as their own self-contained Go module. The build

process assumes this is the case by default. But it is possible to include a

Pushup project as part of a parent Go module. See the the `-module` option to

`pushup new`.



## Project directory structure



Pushup projects have a particular directory structure that the compiler expects

before building. The most minimal Pushup project would look like:



```

app

├── layouts

├── pages

│   └── index.up

├── pkg

└── static

go.mod

```



## Pages



Pushup pages are the main units in Pushup. They are a combination of logic and

content. It may be helpful to think of them as both the controller and the view

in a MVC-like system, but colocated together in the same file.



They are also the basis of file-based routing: the name of the Pushup file,

minus the .up extension, is mapped to the portion of the URL path for

routing.



## Layouts



Layouts are HTML templates that used in common across multiple pages. They are

just HTML, with Pushup syntax as necessary. Each page renders its contents, and

then the layout inserts the page contents into the template with the

`^outputSection("contents")` Pushup expression.



## Static media



Static media files like CSS, JS, and images, can be added to the `app/static`

project directory. These will be embedded directly in the project executable

when it is built, and are accessed via a straightforward mapping under the

"/static/" URL path.



## File-based routing



Pushup maps file locations to URL route paths. So `about.up` becomes

`/about`, and `foo/bar/baz.up` becomes `/foo/bar/baz`. More TK ...



You can print a list of the app's routes with the command:



```shell

pushup routes

```



### Dynamic routes



If the filename of a Pushup page starts with a `$` dollar sign, the portion

of the URL path that matches will be available to the page via the `getParam()`

Pushup API method.



For example, let's say there is a Pushup page at `app/pages/people/$id.up`.

If a browser visits the URL `/people/1234`, the page can access it like a named

parameter with the API method `getParam()`, for example:



```pushup

ID: ^getParam(req, "id")


```



would output:



```html

ID: 1234


```



The name of the parameter is the word following the `$` dollar sign, up to a dot

or a slash. Conceptually, the URL route is `/people/:id`, where `:id` is the

named parameter that is substituted for the actual value in the request URL.



Directories can be dynamic, too. `app/pages/products/$pid/details.up` maps

to `/products/:pid/details`.



Multiple named parameters are allowed, for example, `app/pages/users/$uid/projects/$pid.up`

maps to `/users/:uid/projects/:pid`.



## Enhanced hypertext



### Inline partials



Inline partials allow pages to denote subsections of themselves, and allow

for these subsections (the inline partials) to be rendered and returned to

the client independently, without having to render the entire enclosing page.



Typically, partials in templating languages are stored in their own files,

which are then transcluded into other templates. Inline partials, however, are

partials declared and defined in-line a parent or including template.



Inline partials are useful when combined with enhanced hypertext solutions

(eg., [htmx](https://htmx.org/)). The reason is that these sites make AJAX

requests for partial HTML responses to update portions of an already-loaded

document. Partial responses should not have enclosing markup such as base

templates applied by the templating engine, since that would break the of the

document they are being inserted into. Inline partials in Pushup automatically

disable layouts so that partial responses have just the content they define.



The ability to quickly define partials, and not have to deal with complexities

like toggling off layouts, makes it easier to build enhanced hypertext sites.



## Basic web framework functionality



All modern web frameworks should implement a standard set of functionality,

spanning from safety to convenience. As of this writing, Pushup does not yet

implement them all, but aspires to prior to any public release.



### Escaping



By default, all content is HTML-escaped, so in general it is safe to directly

place user-supplied data into Pushup pages. (Note that the framework does

not (yet) do this in your Go code, data from form submissions and URL queries

should be validated and treated as unsafe.)



For example, if you wanted to display on the page the query a user searched for,

this is safe:



```pushup

^{ query := req.FormValue("query") }

You search for: ^query


```



## Pushup syntax



### How it works



Pushup is a mix of a new syntax consisting of Pushup directives and keywords,

Go code, and HTML markup.



Parsing a .up file always starts out in HTML mode, so you can just put

plain HTML in a file and that's a valid Pushup page.



When the parser encounters a '^' character (caret, ASCII 0x5e) while in

HTML mode, it switches to parsing Pushup syntax, which consists of simple

directives, control flow statements, block delimiters, and Go expressions. It

then switches to the Go code parser. Once it detects the end of the directive,

statement, or expression, it switches back to HTML mode, and parsing continues

in a similar fashion.



Pushup uses the tokenizers from the [go/scanner][scannerpkg] and

[golang.org/x/net/html][htmlpkg] packages, so it should be able to handle

any valid syntax from either language.



### Directives



#### `^import`



Use `^import` to import a Go package into the current Pushup page. The syntax

for `^import` is the same as a regular [Go import declaration](https://go.dev/ref/spec#Import_declarations)



Example:



```pushup

^import "strings"

^import "strconv"

```



```pushup

^import . "strings"

```



#### `^layout`



Layouts are HTML templates that enclose the contents of a Pushup page.



The `^layout` directive instructs Pushup what layout to apply the contents of

the current page.



The name of the layout following the directive is the filename in the

`layouts` directory minus the `.up` extension. For example, `^layout main`

would try to apply the layout located at `app/layouts/main.up`.



`^layout` is optional - if it is not specified, pages automatically get the

"default" layout (`app/layouts/default.up`).



Example:



```pushup

^layout homepage

```



##### `^layout !` - no layout



A page may choose to have no layout applied - that is, the contents of the page

itself are sent directly to the client with no enclosing template. In this case,

use the `!` name:



```pushup

^layout !

```



### Go code blocks



#### `^{`



To include statements of Go in a Pushup page, type `^{` followed by your

Go code, terminating with a closing `}`.



The scope of a `^{ ... }` in the compiled Go code is equal to its surrounding

markup, so you can define a variable and immediately use it:



```pushup

^{

	name := "world"

}

Hello, ^name!


```



Because the Pushup parser is only looking for a balanced closing `}`, blocks

can be one-liners:



```pushup

^{ name := "world"; greeting := "Hello" }

^greeting, ^name!


```



A Pushup page can have zero or many `^{ ... }` blocks.



#### `^handler`



A handler is similar to `^{ ... }`. The difference is that there may be at most

one handler per page, and it is run prior to any other code or markup on the

page.



A handler is the appropriate place to do "controller"-like (in the MVC sense)

actions, such as HTTP redirects and errors. In other words, any control flow

based on the nature of the request, for example, redirecting after a successful

POST to create a new object in a CRUD operation.



Example:



```pushup

^handler {

    if req.Method == "POST" && formValid(req) {

		if err := createObjectFromForm(req.Form); err == nil {

			return http.Redirect(w, req, "/success/", http.StatusSeeOther)

			return nil

		} else {

			// error handling

			...

	}

	...

}

...

```



Note that handlers (and all Pushup code) run in a method on a receiver that

implements Pushup's `Responder` interface, which is



```go

interface Responder {

	Respond(http.ResponseWriter, *http.Request) error

}

```



To exit from a page early in a handler (i.e., prior to any normal content being

rendered), return from the method with a nil (for success) or an error (which

will in general respond with HTTP 500 to the client).



### Control flow statements



#### `^if`



`^if` takes a boolean Go expression and a block to conditionally render.



Example:



```pushup

^if query := req.FormValue("query"); query != "" {

	
Query: ^query


}

```



#### `^for`



`^for` takes a Go "for" statement condition, clause, or range, and a block,

and repeatedly executes the block.



Example:



```pushup

^for i := 0; i < 10; i++ {

	
Number ^i


}

```



### Expressions



#### Simple expressions



Simple Go expressions can be written with just `^` followed by the expression.

"Simple" means:



-   variable names (eg., `^x`)

-   dotted field name access of structs (eg., `^account.name`)

-   function and method calls (eg., `^strings.Repeat("x", 3)`)

-   index expressions (eg., `a[x]`)



Example:



```pushup

^{ name := "Paul" }

Hello, ^name!


```



Outputs:



```html

Hello, Paul!


```



Notice that the parser stops on the "!" because it knows it is not part of a

Go variable name.



Example:



```pushup

The URL path: ^req.URL.Path


```



Outputs:



```html

The URL path: /foo/bar


```



Example:



```pushup

^import "strings"

^strings.Repeat("Hello", 3)


```



Outputs:



```html

HelloHelloHello


```



#### Explicit expressions



Explicit expressions are written with `^` and followed by any valid Go

expression grouped by parentheses.



Example:



```pushup

^{ numPeople := 4 }

With ^numPeople people there are ^(numPeople * 2) hands


```



Outputs:



```html

With 4 people there are 8 hands


```



### Layout and templates



#### `^section`



Pushup layouts can have sections within the HTML document that Pushup pages

can define with their own content to be rendered into those locations.



For example, a layout could have a sidebar section, and each page can set

its own sidebar content.



In a Pushup page, sections are defined with the keyword like so:



```pushup

^section sidebar {

    

        
This is my sidebar content


        
More to come


    

}

```



Layouts can output sections with the `outputSection` function.



```pushup



    ^outputSection("sidebar")



```



Layouts can also make sections optional, by first checking if a page has set a

section with `sectionDefined()`, which returns a boolean.



```pushup

^if sectionDefined("sidebar") {

    

        ^outputSection("sidebar")

    

}

```



Checking for if a section was set by a page lets a layout designer provide

default markup that can be overridden by a page.



```pushup

^if sectionDefined("title") {

    

        ^outputSection("title")

    

} ^else {

    Welcome to our site

}

```



#### `^partial`



Pushup pages can declare and define inline partials with the `^partial`

keyword.



```pushup

...



    
Elements


    ^partial list {

            
    

                    
  • Ag
    • 

                    
  • Na
    • 

                    
  • C
    • 

                


    }



...

```



A request to the page containing the initial partial will render normally,

as if the block where not wrapped in `^partial list {` ... `}`.



A request to the page with the name of the partial appended to the URL path

will respond with just the content scoped by the partial block.



For example, if the page above had the route `/elements/`, then a request to

`/elements/list` would output:



```html

    

        
  • Ag
    • 

        
  • Na
    • 

        
  • C
    • 



```



Inline partials can nest arbitrarily deep.



```pushup

...

^partial leagues {

    
Leagues


    ^partial teams {

        
Teams


        ^partial players {

            
Players


        }

    }

}

...

```



To request a nested partial, make sure the URL path is preceded by

each containing partial's name and a forward slash, for example,

`/sports/leagues/teams/players`.



[token]: https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/creating-a-personal-access-token

[scannerpkg]: https://pkg.go.dev/go/scanner#Scanner

[htmlpkg]: https://pkg.go.dev/golang.org/x/net/html#Tokenizer



## Vim syntax file



There is a vim plugin in the `vim-pushup` directory. You should be able to symlink it into your plugin manager's path. Alternatively, to install it manually:



-   Locate or create a `syntax` directory in your vim config directory (Usually `~/.vim/syntax` for vim or `~/.config/nvim/syntax` for neovim)

-   Copy [`syntax/pushup.vim`](https://github.com/adhocteam/pushup/blob/main/vim-pushup/syntax/pushup.vim) into that directory

-   Locate or create a `ftdetect` directory in your vim config directory (Usually `~/.vim/ftdetect` for vim or `~/.config/nvim/ftdetect` for neovim)

-   Copy [`ftdetect/pushup.vim`](https://github.com/adhocteam/pushup/blob/main/vim-pushup/ftdetect/pushup.vim) into that directory