github.com/shippio/gqlgen@v0.0.0-20220912092219-633ea699ef07/README.md (about) 1  2 3 4 # gqlgen [](https://github.com/99designs/gqlgen/actions) [](https://coveralls.io/github/99designs/gqlgen?branch=master) [](https://goreportcard.com/report/github.com/99designs/gqlgen) [](https://pkg.go.dev/github.com/99designs/gqlgen) [](http://gqlgen.com/) 5 6 ## What is gqlgen? 7 8 [gqlgen](https://github.com/99designs/gqlgen) is a Go library for building GraphQL servers without any fuss.<br/> 9 10 - **gqlgen is based on a Schema first approach** — You get to Define your API using the GraphQL [Schema Definition Language](http://graphql.org/learn/schema/). 11 - **gqlgen prioritizes Type safety** — You should never see `map[string]interface{}` here. 12 - **gqlgen enables Codegen** — We generate the boring bits, so you can focus on building your app quickly. 13 14 Still not convinced enough to use **gqlgen**? Compare **gqlgen** with other Go graphql [implementations](https://gqlgen.com/feature-comparison/) 15 16 ## Quick start 17 1. [Initialise a new go module](https://golang.org/doc/tutorial/create-module) 18 19 mkdir example 20 cd example 21 go mod init example 22 23 2. Add `github.com/99designs/gqlgen` to your [project's tools.go](https://github.com/golang/go/wiki/Modules#how-can-i-track-tool-dependencies-for-a-module) 24 25 printf '// +build tools\npackage tools\nimport _ "github.com/99designs/gqlgen"' | gofmt > tools.go 26 go mod tidy 27 28 3. Initialise gqlgen config and generate models 29 30 go run github.com/99designs/gqlgen init 31 32 4. Start the graphql server 33 34 go run server.go 35 36 More help to get started: 37 - [Getting started tutorial](https://gqlgen.com/getting-started/) - a comprehensive guide to help you get started 38 - [Real-world examples](https://github.com/99designs/gqlgen/tree/master/_examples) show how to create GraphQL applications 39 - [Reference docs](https://pkg.go.dev/github.com/99designs/gqlgen) for the APIs 40 41 ## Reporting Issues 42 43 If you think you've found a bug, or something isn't behaving the way you think it should, please raise an [issue](https://github.com/99designs/gqlgen/issues) on GitHub. 44 45 ## Contributing 46 47 We welcome contributions, Read our [Contribution Guidelines](https://github.com/99designs/gqlgen/blob/master/CONTRIBUTING.md) to learn more about contributing to **gqlgen** 48 ## Frequently asked questions 49 50 ### How do I prevent fetching child objects that might not be used? 51 52 When you have nested or recursive schema like this: 53 54 ```graphql 55 type User { 56 id: ID! 57 name: String! 58 friends: [User!]! 59 } 60 ``` 61 62 You need to tell gqlgen that it should only fetch friends if the user requested it. There are two ways to do this; 63 64 - #### Using Custom Models 65 66 Write a custom model that omits the friends field: 67 68 ```go 69 type User struct { 70 ID int 71 Name string 72 } 73 ``` 74 75 And reference the model in `gqlgen.yml`: 76 77 ```yaml 78 # gqlgen.yml 79 models: 80 User: 81 model: github.com/you/pkg/model.User # go import path to the User struct above 82 ``` 83 84 - #### Using Explicit Resolvers 85 86 If you want to Keep using the generated model, mark the field as requiring a resolver explicitly in `gqlgen.yml` like this: 87 88 ```yaml 89 # gqlgen.yml 90 models: 91 User: 92 fields: 93 friends: 94 resolver: true # force a resolver to be generated 95 ``` 96 97 After doing either of the above and running generate we will need to provide a resolver for friends: 98 99 ```go 100 func (r *userResolver) Friends(ctx context.Context, obj *User) ([]*User, error) { 101 // select * from user where friendid = obj.ID 102 return friends, nil 103 } 104 ``` 105 106 You can also use inline config with directives to achieve the same result 107 108 ```graphql 109 directive @goModel(model: String, models: [String!]) on OBJECT 110 | INPUT_OBJECT 111 | SCALAR 112 | ENUM 113 | INTERFACE 114 | UNION 115 116 directive @goField(forceResolver: Boolean, name: String) on INPUT_FIELD_DEFINITION 117 | FIELD_DEFINITION 118 119 type User @goModel(model: "github.com/you/pkg/model.User") { 120 id: ID! @goField(name: "todoId") 121 friends: [User!]! @goField(forceResolver: true) 122 } 123 ``` 124 125 ### Can I change the type of the ID from type String to Type Int? 126 127 Yes! You can by remapping it in config as seen below: 128 129 ```yaml 130 models: 131 ID: # The GraphQL type ID is backed by 132 model: 133 - github.com/99designs/gqlgen/graphql.IntID # a go integer 134 - github.com/99designs/gqlgen/graphql.ID # or a go string 135 ``` 136 137 This means gqlgen will be able to automatically bind to strings or ints for models you have written yourself, but the 138 first model in this list is used as the default type and it will always be used when: 139 140 - Generating models based on schema 141 - As arguments in resolvers 142 143 There isn't any way around this, gqlgen has no way to know what you want in a given context. 144 145 ### Why do my interfaces have getters? Can I disable these? 146 These were added in v0.17.14 to allow accessing common interface fields without casting to a concrete type. 147 However, certain fields, like Relay-style Connections, cannot be implemented with simple getters. 148 149 If you'd prefer to not have getters generated in your interfaces, you can add the following in your `gqlgen.yml`: 150 ```yaml 151 # gqlgen.yml 152 omit_getters: true 153 ``` 154 155 ## Other Resources 156 157 - [Christopher Biscardi @ Gophercon UK 2018](https://youtu.be/FdURVezcdcw) 158 - [Introducing gqlgen: a GraphQL Server Generator for Go](https://99designs.com.au/blog/engineering/gqlgen-a-graphql-server-generator-for-go/) 159 - [Dive into GraphQL by Iván Corrales Solera](https://medium.com/@ivan.corrales.solera/dive-into-graphql-9bfedf22e1a) 160 - [Sample Project built on gqlgen with Postgres by Oleg Shalygin](https://github.com/oshalygin/gqlgen-pg-todo-example) 161 - [Hackernews GraphQL Server with gqlgen by Shayegan Hooshyari](https://www.howtographql.com/graphql-go/0-introduction/)