go-beget

Generate serializable and (somewhat) typesafe search requests to pass around.

The intent is not to recreate Rails, but rather provide a baseline for you to fork to help generate all your boilerplate just the way you like it.

This is still a work in progress.

The basics

Install beget by running go get -u github.com/brianstarke/go-beget/...

Add beget tags to a struct for which you want to create SearchRequests for and add the go:generate comment.

struct is the struct you want the go-beget generator to look at, table is the name of the database table (if you want to use optional SQL statement generation). impls takes a comma separated list of helpers you'd like to auto-generate.

• sql will generate a SQLSearcher/SQLCreator/SQLUpdater (currently, sql implementation has only been tested on PostgreSQL).
• gin will generate gin gonic handlers that use the generated SQLSearcher/SQLCreator/SQLUpdater stuff.

Within the beget tag, add search to the fields you'd like to be searchable, create to the fields you'd like to be inserted by the generated Creator and update to the fields you want to allow to updated via an Updater.

Generally you'd leave the ID field without a create tag if your database is assigning the IDs.

package types

//go:generate searcher -struct=Thing -table=things -impls=sql,gin
//go:generate creator -struct=Thing -table=things -impls=sql,gin
//go:generate updater -struct=Thing -table=things -impls=sql,gin

// Thing has characteristics
type Thing struct {
	ID          int64  `beget:"search" json:"id" db:"id"`
	Color       string `beget:"search,create" json:"color" db:"color"`
	Description string `beget:"search,create" json:"description" db:"description"`
	Length      int    `beget:"search,create,update" json:"length" db:"length"`
	Height      int    `beget:"search,create,update" json:"height" db:"height"`
}

NOTE: For now, go-beget expects that you keep your types in some other package and will generate it's code into a directory called search (or update or create) as a peer of wherever the type is.

Run go generate ./...

[go-beget/searcher] Generating searcher for Thing
[go-beget/searcher] ../search does not exist, I'll create it
[go-beget/searcher] SearchRequest generated ../search/thingSearchRequest.go
[go-beget/searcher] SQLSearcher generated ../search/thingSQLSearcher.go
[go-beget/searcher] GinSearcher generated ../search/thingGinSearcher.go
[go-beget/creator] Generating creator for Thing
[go-beget/creator] ../create does not exist, I'll create it
[go-beget/creator] SQLCreator generated ../create/thingSQLCreator.go
[go-beget/creator] GinCreator generated ../create/thingGinCreator.go
[go-beget/updater] Generating updater for Thing
[go-beget/updater] ../update does not exist, I'll create it
[go-beget/updater] UpdateRequest generated ../update/thingUpdateRequest.go
[go-beget/updater] SQLUpdater generated ../update/thingSQLUpdater.go
[go-beget/updater] GinUpdater generated ../update/thingGinUpdater.go

Example of using a generated search request.

var sr search.ThingSearchRequest

sr.Fields = []search.ThingField{
  search.ThingColor,
  search.ThingHeight,
}

sr.AddFilter(
  search.ThingColor,
  "red",
  searcher.EQ,
  searcher.AND)

sr.SetOrderBy(search.ThingHeight, false)

sr.Limit = 10

jsonb, _ := json.MarshalIndent(sr, "", "  ")

log.Println(string(jsonb))

searcher.GenerateSelectSQL(&sr)

This outputs

2016/03/03 15:47:05 {
  "limit": 10,
  "filters": [
    {
      "field": "color",
      "value": "red",
      "operator": "EQ",
      "condition": "AND"
    }
  ],
  "orderBy": {
    "field": "height",
    "desc": false
  },
  "fields": [
    "color",
    "height"
  ]
}
[go-beget/searcher] SELECT SQL generated - SELECT color, height FROM things WHERE (color = $1) ORDER BY height LIMIT 10

Using SQLSearchers

You can use a generated searcher to execute SearchRequests or pull single results by a particular field. The latter is useful for doing a get by ID sort of thing.

// construct the search request
var sr search.ThingSearchRequest

sr.AddFilter(
  search.ThingColor,
  "red",
  searcher.EQ,
  searcher.AND)

sr.SetOrderBy(search.ThingHeight, false)
sr.Limit = 10
sr.Offset = 2

// run the search request (where db is a working *sqlx.DB instance)
things, err := search.NewSQLThingSearcher(db).Search(sr)
// do things with results, check error etc...

Or to simply just get a single result by a particular field...

thing, err := search.NewSQLThingSearcher(db).GetByField(search.ThingID, 16)
// do things with result, check error etc...

Using GinSearchers/GinCreators

If you also generated the gin gonic handlers, you can wire them up in your routes like so:

router.PUT("/thing", create.NewThingCreateHandler(db)) 				// create
router.POST("/thing", search.NewThingSearchHandler(db))  			// search
router.GET("/thing/:id", search.NewThingGetByIDHandler(db)) 	// get
router.PATCH("/thing", updater.NewThingUpdateHandler(db)) 		// update

The generated routes expect JSON and return JSON. On error, they return status code 500 and the error in a JSON struct like this:

{
	"error": "Your error here"
}

On success they return 200 and the result as JSON.

Sample JSON SearchRequest

{
    "filters":[{
      "field": "color",
      "value": "RED",
      "operator": "EQ",
      "condition": "AND"
    },
		{
			"field": "size",
			"value": 13,
			"operator": "GT",
			"condition": "AND"
		}],
    "fields": ["height", "type"],
    "orderBy": {
        "field": "createdAt",
        "desc": true
    },
    "limit":20,
    "offset": 2
}

TODO document the creator usage

TODO document the updater usage

Generator templates

go-beget uses the excellent go-bindata tool to compile it's templates in to the executable for easier command line use.

Therefore, if you make any changes to the templates, you must install go-bindata (go get -u github.com/jteeuwen/go-bindata/...).

Then ./rebuild_templates.sh from the root of this project.

TODO

• add an AddField method
• make all generated code pass golint
• break dependency on sqlx and gin?
• generate deleters?
• add fake/mock implementations for testing
• support XML?