Add support for custom variable and response types (#536)

* Custom variable and response types.  This allows me to use my existing
code in some or all of the request/response.

* use typedefs instead so that we don't generate unused code

* Use the custom response type as the first field of ResponseData

---------

Co-authored-by: Mark Riley <mriley@researchinnovations.com>

Author: markrileybot

graphql_client_cli/src/generate.rs

@@ -23,6 +23,8 @@ pub(crate) struct CliCodegenParams {
     pub custom_scalars_module: Option<String>,
     pub fragments_other_variant: bool,
     pub external_enums: Option<Vec<String>>,
+    pub custom_variable_types: Option<String>,
+    pub custom_response_type: Option<String>,
 }
 
 const WARNING_SUPPRESSION: &str = "#![allow(clippy::all, warnings)]";
@@ -41,6 +43,8 @@ pub(crate) fn generate_code(params: CliCodegenParams) -> CliResult<()> {
         custom_scalars_module,
         fragments_other_variant,
         external_enums,
+        custom_variable_types,
+        custom_response_type,
     } = params;
 
     let deprecation_strategy = deprecation_strategy.as_ref().and_then(|s| s.parse().ok());
@@ -89,6 +93,14 @@ pub(crate) fn generate_code(params: CliCodegenParams) -> CliResult<()> {
 
         options.set_custom_scalars_module(custom_scalars_module);
     }
+    
+    if let Some(custom_variable_types) = custom_variable_types {
+        options.set_custom_variable_types(custom_variable_types.split(",").map(String::from).collect());
+    }
+    
+    if let Some(custom_response_type) = custom_response_type {
+        options.set_custom_response_type(custom_response_type);
+    }
 
     let gen = generate_module_token_stream(query_path.clone(), &schema_path, options)
         .map_err(|err| Error::message(format!("Error generating module code: {}", err)))?;

graphql_client_cli/src/main.rs

@@ -94,6 +94,14 @@ enum Cli {
         /// List of externally defined enum types. Type names must match those used in the schema exactly
         #[clap(long = "external-enums", num_args(0..), action(clap::ArgAction::Append))]
         external_enums: Option<Vec<String>>,
+        /// Custom variable types to use
+        /// --custom-variable-types='external_crate::MyStruct,external_crate::MyStruct2'
+        #[clap(long = "custom-variable_types")]
+        custom_variable_types: Option<String>,
+        /// Custom response type to use
+        /// --custom-response-type='external_crate::MyResponse'
+        #[clap(long = "custom-response-type")]
+        custom_response_type: Option<String>,
     },
 }
 
@@ -131,7 +139,9 @@ fn main() -> CliResult<()> {
             selected_operation,
             custom_scalars_module,
             fragments_other_variant,
-            external_enums,
+            external_enums, 
+            custom_variable_types, 
+            custom_response_type,
         } => generate::generate_code(generate::CliCodegenParams {
             query_path,
             schema_path,
@@ -145,6 +155,8 @@ fn main() -> CliResult<()> {
             custom_scalars_module,
             fragments_other_variant,
             external_enums,
+            custom_variable_types,
+            custom_response_type,
         }),
     }
 }

graphql_client_codegen/src/codegen.rs

@@ -42,7 +42,7 @@ pub(crate) fn response_for_query(
         generate_variables_struct(operation_id, &variable_derives, options, &query);
 
     let definitions =
-        render_response_data_fields(operation_id, options, &query).render(&response_derives);
+        render_response_data_fields(operation_id, options, &query)?.render(&response_derives);
 
     let q = quote! {
         use #serde::{Serialize, Deserialize};

graphql_client_codegen/src/codegen/inputs.rs

@@ -15,10 +15,18 @@ pub(super) fn generate_input_object_definitions(
     variable_derives: &impl quote::ToTokens,
     query: &BoundQuery<'_>,
 ) -> Vec<TokenStream> {
+    let custom_variable_types = options.custom_variable_types();
     all_used_types
         .inputs(query.schema)
-        .map(|(_input_id, input)| {
-            if input.is_one_of {
+        .map(|(input_id, input)| {
+            let custom_variable_type = query.query.variables.iter()
+                .enumerate()
+                .find(|(_, v) | v.r#type.id.as_input_id().is_some_and(|i| i == input_id))
+                .map(|(index, _)| custom_variable_types.get(index))
+                .flatten();
+            if let Some(custom_type) = custom_variable_type {
+                generate_type_def(input, options, custom_type)
+            } else if input.is_one_of {
                 generate_enum(input, options, variable_derives, query)
             } else {
                 generate_struct(input, options, variable_derives, query)
@@ -27,6 +35,18 @@ pub(super) fn generate_input_object_definitions(
         .collect()
 }
 
+fn generate_type_def(
+    input: &StoredInputType,
+    options: &GraphQLClientCodegenOptions,
+    custom_type: &String,
+) -> TokenStream {
+    let custom_type = syn::parse_str::<syn::Path>(custom_type).unwrap();
+    let normalized_name = options.normalization().input_name(input.name.as_str());
+    let safe_name = keyword_replace(normalized_name);
+    let struct_name = Ident::new(safe_name.as_ref(), Span::call_site());
+    quote!(pub type #struct_name = #custom_type;)
+}
+
 fn generate_struct(
     input: &StoredInputType,
     options: &GraphQLClientCodegenOptions,

graphql_client_codegen/src/codegen/selection.rs

@@ -13,17 +13,19 @@ use crate::{
     schema::{Schema, TypeId},
     type_qualifiers::GraphqlTypeQualifier,
     GraphQLClientCodegenOptions,
+    GeneralError,
 };
 use heck::*;
 use proc_macro2::{Ident, Span, TokenStream};
 use quote::{quote, ToTokens};
 use std::borrow::Cow;
+use syn::Path;
 
 pub(crate) fn render_response_data_fields<'a>(
     operation_id: OperationId,
     options: &'a GraphQLClientCodegenOptions,
     query: &'a BoundQuery<'a>,
-) -> ExpandedSelection<'a> {
+) -> Result<ExpandedSelection<'a>, GeneralError> {
     let operation = query.query.get_operation(operation_id);
     let mut expanded_selection = ExpandedSelection {
         query,
@@ -38,6 +40,18 @@ pub(crate) fn render_response_data_fields<'a>(
         name: Cow::Borrowed("ResponseData"),
     });
 
+    if let Some(custom_response_type) = options.custom_response_type() {
+        if operation.selection_set.len() == 1 {
+            let selection_id = operation.selection_set[0];
+            let selection_field = query.query.get_selection(selection_id).as_selected_field()
+                .ok_or_else(|| GeneralError(format!("Custom response type {custom_response_type} will only work on fields")))?;
+            calculate_custom_response_type_selection(&mut expanded_selection, response_data_type_id, custom_response_type, selection_id, selection_field);
+            return Ok(expanded_selection);
+        } else {
+            return Err(GeneralError(format!("Custom response type {custom_response_type} requires single selection field")));
+        }
+    }
+
     calculate_selection(
         &mut expanded_selection,
         &operation.selection_set,
@@ -46,7 +60,38 @@ pub(crate) fn render_response_data_fields<'a>(
         options,
     );
 
-    expanded_selection
+    Ok(expanded_selection)
+}
+
+fn calculate_custom_response_type_selection<'a>(
+    context: &mut ExpandedSelection<'a>,
+    struct_id: ResponseTypeId,
+    custom_response_type: &'a String,
+    selection_id: SelectionId,
+    field: &'a SelectedField)
+{
+    let (graphql_name, rust_name) = context.field_name(field);
+    let struct_name_string = full_path_prefix(selection_id, context.query);
+    let field = context.query.schema.get_field(field.field_id);
+    context.push_field(ExpandedField {
+        struct_id,
+        graphql_name: Some(graphql_name),
+        rust_name,
+        field_type_qualifiers: &field.r#type.qualifiers,
+        field_type: struct_name_string.clone().into(),
+        flatten: false,
+        boxed: false,
+        deprecation: field.deprecation(),
+    });
+
+    let struct_id = context.push_type(ExpandedType {
+        name: struct_name_string.into(),
+    });
+    context.push_type_alias(TypeAlias {
+        name: custom_response_type.as_str(),
+        struct_id,
+        boxed: false,
+    });
 }
 
 pub(super) fn render_fragment<'a>(
@@ -557,14 +602,14 @@ impl<'a> ExpandedSelection<'a> {
 
             // If the type is aliased, stop here.
             if let Some(alias) = self.aliases.iter().find(|alias| alias.struct_id == type_id) {
-                let fragment_name = Ident::new(alias.name, Span::call_site());
-                let fragment_name = if alias.boxed {
-                    quote!(Box<#fragment_name>)
+                let type_name = syn::parse_str::<Path>(alias.name).unwrap();
+                let type_name = if alias.boxed {
+                    quote!(Box<#type_name>)
                 } else {
-                    quote!(#fragment_name)
+                    quote!(#type_name)
                 };
                 let item = quote! {
-                    pub type #struct_name = #fragment_name;
+                    pub type #struct_name = #type_name;
                 };
                 items.push(item);
                 continue;

graphql_client_codegen/src/codegen_options.rs

@@ -49,6 +49,10 @@ pub struct GraphQLClientCodegenOptions {
     skip_serializing_none: bool,
     /// Path to the serde crate.
     serde_path: syn::Path,
+    /// list of custom type paths to use for input variables
+    custom_variable_types: Option<Vec<String>>,
+    /// Custom response type path
+    custom_response_type: Option<String>,
 }
 
 impl GraphQLClientCodegenOptions {
@@ -71,6 +75,8 @@ impl GraphQLClientCodegenOptions {
             fragments_other_variant: Default::default(),
             skip_serializing_none: Default::default(),
             serde_path: syn::parse_quote!(::serde),
+            custom_variable_types: Default::default(),
+            custom_response_type: Default::default(),
         }
     }
 
@@ -138,6 +144,26 @@ impl GraphQLClientCodegenOptions {
         self.response_derives = Some(response_derives);
     }
 
+    /// Type use as the response type
+    pub fn custom_response_type(&self) -> Option<&String> {
+        self.custom_response_type.as_ref()
+    }
+
+    /// Type use as the response type
+    pub fn set_custom_response_type(&mut self, response_type: String) {
+        self.custom_response_type = Some(response_type);
+    }
+
+    /// list of custom type paths to use for input variables
+    pub fn custom_variable_types(&self) -> Vec<String> {
+        self.custom_variable_types.clone().unwrap_or_default()
+    }
+
+    /// list of custom type paths to use for input variables
+    pub fn set_custom_variable_types(&mut self, variables_types: Vec<String>) {
+        self.custom_variable_types = Some(variables_types);
+    }
+
     /// The deprecation strategy to adopt.
     pub fn set_deprecation_strategy(&mut self, deprecation_strategy: DeprecationStrategy) {
         self.deprecation_strategy = Some(deprecation_strategy);

graphql_client_codegen/src/query.rs

@@ -58,7 +58,7 @@ pub(crate) struct ResolvedFragmentId(u32);
 
 #[allow(dead_code)]
 #[derive(Debug, Clone, Copy)]
-pub(crate) struct VariableId(u32);
+pub(crate) struct VariableId(pub u32);
 
 pub(crate) fn resolve<'doc, T>(
     schema: &Schema,
@@ -512,7 +512,7 @@ pub(crate) struct Query {
     operations: Vec<ResolvedOperation>,
     selection_parent_idx: BTreeMap<SelectionId, SelectionParent>,
     selections: Vec<Selection>,
-    variables: Vec<ResolvedVariable>,
+    pub(crate) variables: Vec<ResolvedVariable>,
 }
 
 impl Query {

graphql_client_codegen/src/tests/mod.rs

@@ -42,6 +42,35 @@ fn schema_with_keywords_works() {
     };
 }
 
+#[test]
+fn blended_custom_types_works() {
+    let query_string = KEYWORDS_QUERY;
+    let schema_path = build_schema_path(KEYWORDS_SCHEMA_PATH);
+
+    let mut options = GraphQLClientCodegenOptions::new(CodegenMode::Cli);
+    options.set_custom_response_type("external_crate::Transaction".to_string());
+    options.set_custom_variable_types(vec!["external_crate::ID".to_string()]);
+
+    let generated_tokens =
+        generate_module_token_stream_from_string(query_string, &schema_path, options)
+            .expect("Generate keywords module");
+
+    let generated_code = generated_tokens.to_string();
+
+    // Parse generated code. Variables and returns should be replaced with custom types
+    let r: syn::parse::Result<proc_macro2::TokenStream> = syn::parse2(generated_tokens);
+    match r {
+        Ok(_) => {
+            // Variables and returns should be replaced with custom types
+            assert!(generated_code.contains("pub type SearchQuerySearch = external_crate :: Transaction"));
+            assert!(generated_code.contains("pub type extern_ = external_crate :: ID"));
+        }
+        Err(e) => {
+            panic!("Error: {}\n Generated content: {}\n", e, &generated_code);
+        }
+    };
+}
+
 #[test]
 fn fragments_other_variant_should_generate_unknown_other_variant() {
     let query_string = FOOBARS_QUERY;

graphql_query_derive/src/attributes.rs

@@ -295,4 +295,44 @@ mod test {
             vec!["Direction", "DistanceUnit"],
         );
     }
+
+    #[test]
+    fn test_custom_variable_types() {
+        let input = r#"
+            #[derive(Serialize, Deserialize, Debug)]
+            #[derive(GraphQLQuery)]
+            #[graphql(
+                schema_path = "x",
+                query_path = "x",
+                variable_types("extern_crate::Var1", "extern_crate::Var2"),
+            )]
+            struct MyQuery;
+        "#;
+        let parsed: syn::DeriveInput = syn::parse_str(input).unwrap();
+
+        assert_eq!(
+            extract_attr_list(&parsed, "variable_types").ok().unwrap(),
+            vec!["extern_crate::Var1", "extern_crate::Var2"],
+        );
+    }
+
+    #[test]
+    fn test_custom_response_type() {
+        let input = r#"
+            #[derive(Serialize, Deserialize, Debug)]
+            #[derive(GraphQLQuery)]
+            #[graphql(
+                schema_path = "x",
+                query_path = "x",
+                response_type = "extern_crate::Resp",
+            )]
+            struct MyQuery;
+        "#;
+        let parsed: syn::DeriveInput = syn::parse_str(input).unwrap();
+
+        assert_eq!(
+            extract_attr(&parsed, "response_type").ok().unwrap(),
+            "extern_crate::Resp",
+        );
+    }
 }

graphql_query_derive/src/lib.rs

@@ -65,6 +65,8 @@ fn build_graphql_client_derive_options(
     let extern_enums = attributes::extract_attr_list(input, "extern_enums").ok();
     let fragments_other_variant: bool = attributes::extract_fragments_other_variant(input);
     let skip_serializing_none: bool = attributes::extract_skip_serializing_none(input);
+    let custom_variable_types = attributes::extract_attr_list(input, "variable_types").ok();
+    let custom_response_type = attributes::extract_attr(input, "response_type").ok();
 
     let mut options = GraphQLClientCodegenOptions::new(CodegenMode::Derive);
     options.set_query_file(query_path);
@@ -101,6 +103,14 @@ fn build_graphql_client_derive_options(
         options.set_extern_enums(extern_enums);
     }
 
+    if let Some(custom_variable_types) = custom_variable_types {
+        options.set_custom_variable_types(custom_variable_types);
+    }
+    
+    if let Some(custom_response_type) = custom_response_type {
+        options.set_custom_response_type(custom_response_type);
+    }
+
     options.set_struct_ident(input.ident.clone());
     options.set_module_visibility(input.vis.clone());
     options.set_operation_name(input.ident.to_string());