Add an option to provide module for the custom scalar definitions

graphql_client_cli/src/generate.rs

@@ -17,6 +17,7 @@ pub(crate) struct CliCodegenParams {
     pub no_formatting: bool,
     pub module_visibility: Option<String>,
     pub output_directory: Option<PathBuf>,
+    pub custom_scalars_module: Option<String>,
 }
 
 pub(crate) fn generate_code(params: CliCodegenParams) -> Result<()> {
@@ -30,6 +31,7 @@ pub(crate) fn generate_code(params: CliCodegenParams) -> Result<()> {
         query_path,
         schema_path,
         selected_operation,
+        custom_scalars_module,
     } = params;
 
     let deprecation_strategy = deprecation_strategy.as_ref().and_then(|s| s.parse().ok());
@@ -59,6 +61,17 @@ pub(crate) fn generate_code(params: CliCodegenParams) -> Result<()> {
         options.set_deprecation_strategy(deprecation_strategy);
     }
 
+    if let Some(custom_scalars_module) = custom_scalars_module {
+        let custom_scalars_module = syn::parse_str(&custom_scalars_module).with_context(|| {
+            format!(
+                "Invalid custom scalars module path: {}",
+                custom_scalars_module
+            )
+        })?;
+
+        options.set_custom_scalars_module(custom_scalars_module);
+    }
+
     let gen = generate_module_token_stream(query_path.clone(), &schema_path, options).unwrap();
 
     let generated_code = gen.to_string();

graphql_client_cli/src/main.rs

@@ -70,6 +70,10 @@ enum Cli {
         /// file, with the same name and the .rs extension.
         #[structopt(short = "o", long = "output-directory")]
         output_directory: Option<PathBuf>,
+        /// The module where the custom scalar definitions are located.
+        /// --custom-scalars-module='crate::gql::custom_scalars'
+        #[structopt(short = "p", long = "custom-scalars-module")]
+        custom_scalars_module: Option<String>,
     },
 }
 
@@ -101,6 +105,7 @@ fn main() -> anyhow::Result<()> {
             query_path,
             schema_path,
             selected_operation,
+            custom_scalars_module,
         } => generate::generate_code(generate::CliCodegenParams {
             variables_derives,
             response_derives,
@@ -111,6 +116,7 @@ fn main() -> anyhow::Result<()> {
             query_path,
             schema_path,
             selected_operation,
+            custom_scalars_module,
         }),
     }
 }

graphql_client_codegen/src/codegen.rs

@@ -156,7 +156,11 @@ fn generate_scalar_definitions<'a, 'schema: 'a>(
                 proc_macro2::Span::call_site(),
             );
 
-            quote!(type #ident = super::#ident;)
+            if let Some(custom_scalars_module) = options.custom_scalars_module() {
+                quote!(type #ident = #custom_scalars_module::#ident;)
+            } else {
+                quote!(type #ident = super::#ident;)
+            }
         })
 }
 

graphql_client_codegen/src/codegen_options.rs

@@ -2,7 +2,7 @@ use crate::deprecation::DeprecationStrategy;
 use crate::normalization::Normalization;
 use proc_macro2::Ident;
 use std::path::{Path, PathBuf};
-use syn::Visibility;
+use syn::{self, Visibility};
 
 /// Which context is this code generation effort taking place.
 #[derive(Debug)]
@@ -39,6 +39,8 @@ pub struct GraphQLClientCodegenOptions {
     schema_file: Option<PathBuf>,
     /// Normalization pattern for query types and names.
     normalization: Normalization,
+    /// Custom scalar definitions module path
+    custom_scalars_module: Option<syn::Path>,
 }
 
 impl GraphQLClientCodegenOptions {
@@ -56,6 +58,7 @@ impl GraphQLClientCodegenOptions {
             query_file: Default::default(),
             schema_file: Default::default(),
             normalization: Normalization::None,
+            custom_scalars_module: Default::default(),
         }
     }
 
@@ -174,4 +177,14 @@ impl GraphQLClientCodegenOptions {
     pub fn normalization(&self) -> &Normalization {
         &self.normalization
     }
+
+    /// Get the custom scalar definitions module
+    pub fn custom_scalars_module(&self) -> Option<&syn::Path> {
+        self.custom_scalars_module.as_ref()
+    }
+
+    /// Set the custom scalar definitions module
+    pub fn set_custom_scalars_module(&mut self, module: syn::Path) {
+        self.custom_scalars_module = Some(module)
+    }
 }

graphql_query_derive/src/lib.rs

@@ -70,6 +70,7 @@ fn build_graphql_client_derive_options(
 ) -> Result<GraphQLClientCodegenOptions, BoxError> {
     let variables_derives = attributes::extract_attr(input, "variables_derives").ok();
     let response_derives = attributes::extract_attr(input, "response_derives").ok();
+    let custom_scalars_module = attributes::extract_attr(input, "custom_scalars_module").ok();
 
     let mut options = GraphQLClientCodegenOptions::new(CodegenMode::Derive);
     options.set_query_file(query_path);
@@ -92,6 +93,18 @@ fn build_graphql_client_derive_options(
         options.set_normalization(normalization);
     };
 
+    // The user can give a path to a module that provides definitions for the custom scalars.
+    if let Some(custom_scalars_module) = custom_scalars_module {
+        let custom_scalars_module = syn::parse_str(&custom_scalars_module).map_err(|err| {
+            GeneralError(format!(
+                "Invalid custom scalars module path: {}. {}",
+                custom_scalars_module, err
+            ))
+        })?;
+
+        options.set_custom_scalars_module(custom_scalars_module);
+    }
+
     options.set_struct_ident(input.ident.clone());
     options.set_module_visibility(input.vis.clone());
     options.set_operation_name(input.ident.to_string());