124 lines
3.1 KiB
Go
124 lines
3.1 KiB
Go
package generate
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import (
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"fmt"
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"io"
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"io/ioutil"
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"os"
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"strings"
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"text/template"
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"github.com/vektah/gqlparser/ast"
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"github.com/vektah/gqlparser/formatter"
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"github.com/vektah/gqlparser/parser"
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)
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// TODO: package template into the binary using one of those asset thingies
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const tmplFilename = "generate/operation.go.tmpl"
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var tmpl = template.Must(template.ParseFiles(tmplFilename))
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type TemplateParams struct {
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// The name of the package into which to generate the operation-helpers.
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PackageName string
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// The list of operations for which to generate code.
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Operations []OperationParams
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}
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type OperationParams struct {
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// The type-name for the operation's response type.
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ResponseName string
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// The body of the operation's response type (e.g. struct { ... }).
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ResponseType string
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// The type of the operation (query, mutation, or subscription).
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OperationType ast.Operation
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// The name of the operation, from GraphQL.
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OperationName string
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// The documentation for the operation, from GraphQL.
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OperationDoc string
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// The endpoint to which to send queries.
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Endpoint string
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// The body of the operation to send.
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Operation string
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}
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func Generate(specFilename, generatedFilename string) error {
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text, err := ioutil.ReadFile(specFilename)
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if err != nil {
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return fmt.Errorf("could not open query-spec file %v: %v",
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specFilename, err)
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}
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document, graphqlError := parser.ParseQuery(
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&ast.Source{Name: specFilename, Input: string(text)})
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if graphqlError != nil { // ParseQuery returns type *graphql.Error, yuck
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return fmt.Errorf("could not parse query-spec file %v: %v",
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specFilename, graphqlError)
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}
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var out io.Writer
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if generatedFilename == "-" {
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out = os.Stdout
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} else {
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out, err = os.OpenFile(generatedFilename, os.O_RDWR|os.O_CREATE, 0755)
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if err != nil {
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return fmt.Errorf("could not open generated file %v: %v",
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generatedFilename, err)
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}
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}
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// TODO: configure these
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packageName := "example"
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endpoint := "https://api.github.com/graphql"
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operations := make([]OperationParams, len(document.Operations))
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for i, operation := range document.Operations {
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var builder strings.Builder
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f := formatter.NewFormatter(&builder)
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f.FormatQueryDocument(&ast.QueryDocument{
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Operations: ast.OperationList{operation},
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// TODO: handle fragments
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})
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operations[i] = OperationParams{
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OperationType: operation.Operation,
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OperationName: operation.Name,
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OperationDoc: "TODO",
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// TODO: configure this
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ResponseName: operation.Name + "Response",
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ResponseType: "struct{} // TODO",
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Endpoint: endpoint,
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// The newline just makes it format a little nicer
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Operation: "\n" + builder.String(),
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}
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}
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data := TemplateParams{
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PackageName: packageName,
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Operations: operations,
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}
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err = tmpl.Execute(out, data)
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if err != nil {
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return fmt.Errorf("could not render template: %v", err)
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}
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return nil
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}
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func Main() {
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var err error
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defer func() {
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if err != nil {
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fmt.Println(err)
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os.Exit(1)
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}
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}()
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if len(os.Args) != 3 {
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err = fmt.Errorf("usage: %s queries.graphql generated.go", os.Args[0])
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return
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}
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err = Generate(os.Args[1], os.Args[2])
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}
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