feat: implement field commands

src/cli.rs

@@ -36,6 +36,11 @@ pub enum Command {
     #[command(subcommand)]
     command: AppsCommand,
   },
+  #[command(about = "Perform operations against the fields in the instance")]
+  Fields {
+    #[command(subcommand)]
+    command: FieldsCommand,
+  },
 }
 
 #[derive(Debug, PartialEq, Subcommand)]
@@ -61,6 +66,37 @@ pub enum AppsCommand {
   },
 }
 
+#[derive(Debug, PartialEq, Subcommand)]
+pub enum FieldsCommand {
+  #[command(about = "Get information for a list of fields")]
+  List {
+    #[arg(long)]
+    #[arg(short = 'i')]
+    #[arg(help = "App id to get")]
+    app_id: i32,
+    
+    #[command(flatten)]
+    paging: PagingArgs,
+  },
+
+  #[command(about = "Get information about a field")]
+  Get {
+    #[arg(long)]
+    #[arg(short = 'i')]
+    #[arg(help = "Field id to get")]
+    field_id: i32,
+  },
+
+  #[command(about = "Get information for a batch of fields")]
+  BatchGet {
+    #[arg(long)]
+    #[arg(value_delimiter = ',')]
+    #[arg(short = 'i')]
+    #[arg(help = "Comma-separated list of field ids to get")]
+    ids: Vec<i32>,
+  },
+}
+
 #[derive(Debug, PartialEq, Clone, Args, Default)]
 pub struct PagingArgs {
   #[arg(long)]
@@ -79,8 +115,8 @@ where
   I: IntoIterator<Item = T>,
   T: Into<std::ffi::OsString> + Clone,
 {
-  use clap::error::ErrorKind;
   use crate::error::CliError;
+  use clap::error::ErrorKind;
 
   Cli::try_parse_from(args).map_err(|e| match e.kind() {
     ErrorKind::DisplayHelp | ErrorKind::DisplayVersion => CliError::info(e.to_string()),
@@ -206,16 +242,15 @@ mod tests {
         base_url: None,
         pretty: false,
         command: Command::Apps {
-          command: AppsCommand::BatchGet {
-            ids: vec![1, 2, 3],
-          },
+          command: AppsCommand::BatchGet { ids: vec![1, 2, 3] },
         },
       })
     );
   }
 
   #[test]
-  fn parse_cli_from_when_called_with_apps_batch_get_without_ids_it_should_return_cli_with_empty_ids() {
+  fn parse_cli_from_when_called_with_apps_batch_get_without_ids_it_should_return_cli_with_empty_ids()
+   {
     let result = parse_cli_from(["test", "apps", "batch-get"]);
 
     assert_eq!(
@@ -232,7 +267,8 @@ mod tests {
   }
 
   #[test]
-  fn parse_cli_from_when_called_with_apps_batch_get_invalid_id_format_it_should_return_usage_error() {
+  fn parse_cli_from_when_called_with_apps_batch_get_invalid_id_format_it_should_return_usage_error()
+  {
     let result = parse_cli_from(["test", "apps", "batch-get", "--ids", "invalid"]);
 
     assert!(result.is_err());
@@ -284,6 +320,165 @@ mod tests {
     assert!(err.message.contains(env!("CARGO_PKG_DESCRIPTION")));
   }
 
+  #[test]
+  fn parse_cli_from_when_called_with_fields_list_it_should_return_cli() {
+    let result = parse_cli_from(["test", "fields", "list", "--app-id", "10"]);
+
+    assert_eq!(
+      result,
+      Ok(Cli {
+        api_key: None,
+        base_url: None,
+        pretty: false,
+        command: Command::Fields {
+          command: FieldsCommand::List {
+            app_id: 10,
+            paging: PagingArgs::default(),
+          },
+        },
+      })
+    );
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_fields_list_paging_args_it_should_return_cli() {
+    let result = parse_cli_from([
+      "test",
+      "fields",
+      "list",
+      "-i",
+      "10",
+      "--page-number",
+      "2",
+      "--page-size",
+      "25",
+    ]);
+
+    assert_eq!(
+      result,
+      Ok(Cli {
+        api_key: None,
+        base_url: None,
+        pretty: false,
+        command: Command::Fields {
+          command: FieldsCommand::List {
+            app_id: 10,
+            paging: PagingArgs {
+              page_number: Some(2),
+              page_size: Some(25),
+            },
+          },
+        },
+      })
+    );
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_fields_list_missing_app_id_it_should_return_usage_error() {
+    let result = parse_cli_from(["test", "fields", "list"]);
+
+    assert!(result.is_err());
+    let err = result.unwrap_err();
+    assert_eq!(err.code, 2);
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_fields_get_it_should_return_cli() {
+    let result = parse_cli_from(["test", "fields", "get", "--field-id", "123"]);
+
+    assert_eq!(
+      result,
+      Ok(Cli {
+        api_key: None,
+        base_url: None,
+        pretty: false,
+        command: Command::Fields {
+          command: FieldsCommand::Get { field_id: 123 },
+        },
+      })
+    );
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_fields_get_short_flag_it_should_return_cli() {
+    let result = parse_cli_from(["test", "fields", "get", "-i", "123"]);
+
+    assert_eq!(
+      result,
+      Ok(Cli {
+        api_key: None,
+        base_url: None,
+        pretty: false,
+        command: Command::Fields {
+          command: FieldsCommand::Get { field_id: 123 },
+        },
+      })
+    );
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_fields_get_missing_field_id_it_should_return_usage_error() {
+    let result = parse_cli_from(["test", "fields", "get"]);
+
+    assert!(result.is_err());
+    let err = result.unwrap_err();
+    assert_eq!(err.code, 2);
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_fields_batch_get_it_should_return_cli() {
+    let result = parse_cli_from(["test", "fields", "batch-get", "--ids", "1,2,3"]);
+
+    assert_eq!(
+      result,
+      Ok(Cli {
+        api_key: None,
+        base_url: None,
+        pretty: false,
+        command: Command::Fields {
+          command: FieldsCommand::BatchGet { ids: vec![1, 2, 3] },
+        },
+      })
+    );
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_fields_batch_get_without_ids_it_should_return_cli_with_empty_ids()
+  {
+    let result = parse_cli_from(["test", "fields", "batch-get"]);
+
+    assert_eq!(
+      result,
+      Ok(Cli {
+        api_key: None,
+        base_url: None,
+        pretty: false,
+        command: Command::Fields {
+          command: FieldsCommand::BatchGet { ids: vec![] },
+        },
+      })
+    );
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_fields_batch_get_invalid_id_format_it_should_return_usage_error()
+  {
+    let result = parse_cli_from(["test", "fields", "batch-get", "--ids", "invalid"]);
+
+    assert!(result.is_err());
+    let err = result.unwrap_err();
+    assert_eq!(err.code, 2);
+  }
+
+  #[test]
+  fn parse_cli_from_when_called_with_fields_without_subcommand_it_should_return_usage_error() {
+    let result = parse_cli_from(["test", "fields"]);
+
+    assert!(result.is_err());
+    let err = result.unwrap_err();
+    assert_eq!(err.code, 2);
+  }
+
   #[test]
   fn parse_cli_from_when_called_with_version_flag_it_should_return_info_with_code_0() {
     let result = parse_cli_from(["test", "--version"]);
@@ -295,4 +490,3 @@ mod tests {
     assert!(err.message.contains(env!("CARGO_PKG_VERSION")));
   }
 }
-

src/client.rs

@@ -1,5 +1,5 @@
 use onspring::{
-  App, CollectionResponse, OnspringClient, OnspringError, PagedResponse, PagingRequest,
+  App, CollectionResponse, Field, OnspringClient, OnspringError, PagedResponse, PagingRequest,
 };
 
 pub trait OnspringRunner {
@@ -19,6 +19,22 @@ pub trait OnspringRunner {
     &self,
     ids: &[i32],
   ) -> impl std::future::Future<Output = Result<CollectionResponse<App>, OnspringError>> + Send;
+
+  fn list_fields(
+    &self,
+    app_id: i32,
+    paging: Option<PagingRequest>,
+  ) -> impl std::future::Future<Output = Result<PagedResponse<Field>, OnspringError>> + Send;
+
+  fn get_field(
+    &self,
+    field_id: i32,
+  ) -> impl std::future::Future<Output = Result<Field, OnspringError>> + Send;
+
+  fn batch_get_fields(
+    &self,
+    ids: &[i32],
+  ) -> impl std::future::Future<Output = Result<CollectionResponse<Field>, OnspringError>> + Send;
 }
 
 impl OnspringRunner for OnspringClient {
@@ -40,6 +56,22 @@ impl OnspringRunner for OnspringClient {
   async fn batch_get_apps(&self, ids: &[i32]) -> Result<CollectionResponse<App>, OnspringError> {
     self.batch_get_apps(ids).await
   }
+
+  async fn list_fields(
+    &self,
+    app_id: i32,
+    paging: Option<PagingRequest>,
+  ) -> Result<PagedResponse<Field>, OnspringError> {
+    self.list_fields(app_id, paging).await
+  }
+
+  async fn get_field(&self, field_id: i32) -> Result<Field, OnspringError> {
+    self.get_field(field_id).await
+  }
+
+  async fn batch_get_fields(&self, ids: &[i32]) -> Result<CollectionResponse<Field>, OnspringError> {
+    self.batch_get_fields(ids).await
+  }
 }
 
 #[cfg(test)]
@@ -55,6 +87,14 @@ pub mod testing {
     pub list_apps_paging: Mutex<Option<Option<PagingRequest>>>,
     pub get_app_id: Mutex<Option<i32>>,
     pub batch_get_apps_ids: Mutex<Option<Vec<i32>>>,
+
+    pub list_fields_result: Result<PagedResponse<Field>, OnspringError>,
+    pub get_field_result: Result<Field, OnspringError>,
+    pub batch_get_fields_result: Result<CollectionResponse<Field>, OnspringError>,
+    pub list_fields_app_id: Mutex<Option<i32>>,
+    pub list_fields_paging: Mutex<Option<Option<PagingRequest>>>,
+    pub get_field_id: Mutex<Option<i32>>,
+    pub batch_get_fields_ids: Mutex<Option<Vec<i32>>>,
   }
 
   impl Default for MockClient {
@@ -80,6 +120,36 @@ pub mod testing {
         list_apps_paging: Mutex::new(None),
         get_app_id: Mutex::new(None),
         batch_get_apps_ids: Mutex::new(None),
+
+        list_fields_result: Ok(PagedResponse {
+          page_number: None,
+          page_size: None,
+          total_pages: None,
+          total_records: None,
+          items: None,
+        }),
+        get_field_result: Ok(Field {
+          id: 1,
+          app_id: 1,
+          name: None,
+          field_type: None,
+          status: None,
+          is_required: false,
+          is_unique: false,
+          multiplicity: None,
+          list_id: None,
+          values: None,
+          output_type: None,
+          referenced_app_id: None,
+        }),
+        batch_get_fields_result: Ok(CollectionResponse {
+          count: None,
+          items: None,
+        }),
+        list_fields_app_id: Mutex::new(None),
+        list_fields_paging: Mutex::new(None),
+        get_field_id: Mutex::new(None),
+        batch_get_fields_ids: Mutex::new(None),
       }
     }
   }
@@ -136,5 +206,34 @@ pub mod testing {
         Err(err) => Err(clone_onspring_error(err)),
       }
     }
+
+    async fn list_fields(
+      &self,
+      app_id: i32,
+      paging: Option<PagingRequest>,
+    ) -> Result<PagedResponse<Field>, OnspringError> {
+      *self.list_fields_app_id.lock().unwrap() = Some(app_id);
+      *self.list_fields_paging.lock().unwrap() = Some(paging);
+      match &self.list_fields_result {
+        Ok(res) => Ok(res.clone()),
+        Err(err) => Err(clone_onspring_error(err)),
+      }
+    }
+
+    async fn get_field(&self, field_id: i32) -> Result<Field, OnspringError> {
+      *self.get_field_id.lock().unwrap() = Some(field_id);
+      match &self.get_field_result {
+        Ok(res) => Ok(res.clone()),
+        Err(err) => Err(clone_onspring_error(err)),
+      }
+    }
+
+    async fn batch_get_fields(&self, ids: &[i32]) -> Result<CollectionResponse<Field>, OnspringError> {
+      *self.batch_get_fields_ids.lock().unwrap() = Some(ids.to_vec());
+      match &self.batch_get_fields_result {
+        Ok(res) => Ok(res.clone()),
+        Err(err) => Err(clone_onspring_error(err)),
+      }
+    }
   }
 }

src/commands/fields.rs

@@ -0,0 +1,539 @@
+use std::io::Write;
+
+use crate::cli::FieldsCommand;
+use crate::client::OnspringRunner;
+use crate::error::CliResult;
+use crate::output::{CollectionOutput, FieldOutput, PagedOutput, write_json};
+use crate::validation::{paging_request, validate_ids, validate_positive_i32};
+
+pub async fn handle<C: OnspringRunner, W: Write>(
+  command: &FieldsCommand,
+  client: &C,
+  writer: &mut W,
+  pretty: bool,
+) -> CliResult<()> {
+  match command {
+    FieldsCommand::List { app_id, paging } => {
+      validate_positive_i32(*app_id, "app_id")?;
+      let paging = paging_request(paging)?;
+      let response = client.list_fields(*app_id, paging).await?;
+      let output: PagedOutput<FieldOutput> = response.into();
+      write_json(writer, &output, pretty)?;
+    }
+    FieldsCommand::Get { field_id } => {
+      validate_positive_i32(*field_id, "field_id")?;
+      let response = client.get_field(*field_id).await?;
+      let output: FieldOutput = response.into();
+      write_json(writer, &output, pretty)?;
+    }
+    FieldsCommand::BatchGet { ids } => {
+      validate_ids(ids, "ids", Some(100))?;
+      let response = client.batch_get_fields(ids).await?;
+      let output: CollectionOutput<FieldOutput> = response.into();
+      write_json(writer, &output, pretty)?;
+    }
+  }
+
+  Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+  use onspring::{
+    CollectionResponse, Field, FormulaOutputType, ListFieldValue, Multiplicity, OnspringError,
+    PagedResponse,
+  };
+  use uuid::Uuid;
+
+  use crate::cli::PagingArgs;
+  use crate::client::testing::MockClient;
+  use crate::error::CliError;
+
+  fn test_field(id: i32, app_id: i32, name: &str) -> Field {
+    Field {
+      id,
+      app_id,
+      name: Some(name.to_string()),
+      field_type: Some("Text".to_string()),
+      status: Some("Enabled".to_string()),
+      is_required: false,
+      is_unique: false,
+      multiplicity: None,
+      list_id: None,
+      values: None,
+      output_type: None,
+      referenced_app_id: None,
+    }
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_list_succeeds_it_should_write_paged_output() {
+    let mock_client = MockClient {
+      list_fields_result: Ok(PagedResponse {
+        page_number: Some(1),
+        page_size: Some(50),
+        total_pages: Some(1),
+        total_records: Some(1),
+        items: Some(vec![test_field(1, 10, "Test Field")]),
+      }),
+      ..Default::default()
+    };
+
+    let command = FieldsCommand::List {
+      app_id: 10,
+      paging: PagingArgs::default(),
+    };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(result, Ok(()));
+
+    let written = String::from_utf8(buffer).unwrap();
+
+    assert_eq!(
+      written.trim(),
+      r#"{"pageNumber":1,"pageSize":50,"totalPages":1,"totalRecords":1,"items":[{"id":1,"appId":10,"name":"Test Field","type":"Text","status":"Enabled","isRequired":false,"isUnique":false,"multiplicity":null,"listId":null,"values":null,"outputType":null,"referencedAppId":null}]}"#
+    );
+    assert_eq!(*mock_client.list_fields_app_id.lock().unwrap(), Some(10));
+    assert!(
+      mock_client
+        .list_fields_paging
+        .lock()
+        .unwrap()
+        .as_ref()
+        .unwrap()
+        .is_none()
+    );
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_list_with_paging_args_it_should_pass_paging_request() {
+    let mock_client = MockClient {
+      list_fields_result: Ok(PagedResponse {
+        page_number: Some(2),
+        page_size: Some(10),
+        total_pages: Some(5),
+        total_records: Some(50),
+        items: Some(vec![]),
+      }),
+      ..Default::default()
+    };
+
+    let command = FieldsCommand::List {
+      app_id: 10,
+      paging: PagingArgs {
+        page_number: Some(2),
+        page_size: Some(10),
+      },
+    };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(result, Ok(()));
+
+    assert_eq!(*mock_client.list_fields_app_id.lock().unwrap(), Some(10));
+    let paging = mock_client
+      .list_fields_paging
+      .lock()
+      .unwrap()
+      .take()
+      .unwrap()
+      .unwrap();
+    assert_eq!(paging.page_number, 2);
+    assert_eq!(paging.page_size, 10);
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_list_succeeds_pretty_it_should_write_pretty_json() {
+    let mock_client = MockClient {
+      list_fields_result: Ok(PagedResponse {
+        page_number: Some(1),
+        page_size: Some(50),
+        total_pages: Some(1),
+        total_records: Some(1),
+        items: Some(vec![test_field(1, 10, "Test Field")]),
+      }),
+      ..Default::default()
+    };
+
+    let command = FieldsCommand::List {
+      app_id: 10,
+      paging: PagingArgs::default(),
+    };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, true).await;
+
+    assert_eq!(result, Ok(()));
+
+    let written = String::from_utf8(buffer).unwrap();
+
+    let expected = concat!(
+      "{\n",
+      "  \"pageNumber\": 1,\n",
+      "  \"pageSize\": 50,\n",
+      "  \"totalPages\": 1,\n",
+      "  \"totalRecords\": 1,\n",
+      "  \"items\": [\n",
+      "    {\n",
+      "      \"id\": 1,\n",
+      "      \"appId\": 10,\n",
+      "      \"name\": \"Test Field\",\n",
+      "      \"type\": \"Text\",\n",
+      "      \"status\": \"Enabled\",\n",
+      "      \"isRequired\": false,\n",
+      "      \"isUnique\": false,\n",
+      "      \"multiplicity\": null,\n",
+      "      \"listId\": null,\n",
+      "      \"values\": null,\n",
+      "      \"outputType\": null,\n",
+      "      \"referencedAppId\": null\n",
+      "    }\n",
+      "  ]\n",
+      "}"
+    );
+
+    assert_eq!(written.trim(), expected);
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_list_fails_it_should_return_mapped_cli_error() {
+    let mock_client = MockClient {
+      list_fields_result: Err(OnspringError::Api {
+        status_code: 401,
+        message: "Unauthorized".to_string(),
+      }),
+      ..Default::default()
+    };
+
+    let command = FieldsCommand::List {
+      app_id: 10,
+      paging: PagingArgs::default(),
+    };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(
+      result,
+      Err(CliError::runtime("API request failed (401): Unauthorized"))
+    );
+    assert!(buffer.is_empty());
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_list_has_invalid_app_id_it_should_return_usage_error() {
+    let mock_client = MockClient::default();
+
+    let command = FieldsCommand::List {
+      app_id: 0,
+      paging: PagingArgs::default(),
+    };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(
+      result,
+      Err(CliError::usage("app_id must be greater than 0."))
+    );
+    assert!(buffer.is_empty());
+    assert!(mock_client.list_fields_app_id.lock().unwrap().is_none());
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_list_has_invalid_paging_it_should_return_usage_error() {
+    let mock_client = MockClient::default();
+
+    let command = FieldsCommand::List {
+      app_id: 10,
+      paging: PagingArgs {
+        page_number: Some(0),
+        page_size: None,
+      },
+    };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(
+      result,
+      Err(CliError::usage("page_number must be greater than 0."))
+    );
+    assert!(buffer.is_empty());
+    assert!(mock_client.list_fields_paging.lock().unwrap().is_none());
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_get_succeeds_it_should_write_field_output() {
+    let mock_client = MockClient {
+      get_field_result: Ok(Field {
+        id: 123,
+        app_id: 456,
+        name: Some("Status Field".to_string()),
+        field_type: Some("List".to_string()),
+        status: Some("Enabled".to_string()),
+        is_required: true,
+        is_unique: false,
+        multiplicity: Some(Multiplicity::SingleSelect),
+        list_id: Some(789),
+        values: Some(vec![ListFieldValue {
+          id: Uuid::nil(),
+          name: "Active".to_string(),
+          sort_order: 1,
+          numeric_value: Some(1.0),
+          color: Some("#00ff00".to_string()),
+        }]),
+        output_type: Some(FormulaOutputType::Text),
+        referenced_app_id: Some(999),
+      }),
+      ..Default::default()
+    };
+
+    let command = FieldsCommand::Get { field_id: 123 };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(result, Ok(()));
+
+    let written = String::from_utf8(buffer).unwrap();
+
+    assert_eq!(
+      written.trim(),
+      r##"{"id":123,"appId":456,"name":"Status Field","type":"List","status":"Enabled","isRequired":true,"isUnique":false,"multiplicity":"SingleSelect","listId":789,"values":[{"id":"00000000-0000-0000-0000-000000000000","name":"Active","sortOrder":1,"numericValue":1.0,"color":"#00ff00"}],"outputType":"Text","referencedAppId":999}"##
+    );
+    assert_eq!(*mock_client.get_field_id.lock().unwrap(), Some(123));
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_get_succeeds_pretty_it_should_write_pretty_json() {
+    let mock_client = MockClient {
+      get_field_result: Ok(test_field(123, 456, "Test Field")),
+      ..Default::default()
+    };
+
+    let command = FieldsCommand::Get { field_id: 123 };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, true).await;
+
+    assert_eq!(result, Ok(()));
+
+    let written = String::from_utf8(buffer).unwrap();
+
+    let expected = concat!(
+      "{\n",
+      "  \"id\": 123,\n",
+      "  \"appId\": 456,\n",
+      "  \"name\": \"Test Field\",\n",
+      "  \"type\": \"Text\",\n",
+      "  \"status\": \"Enabled\",\n",
+      "  \"isRequired\": false,\n",
+      "  \"isUnique\": false,\n",
+      "  \"multiplicity\": null,\n",
+      "  \"listId\": null,\n",
+      "  \"values\": null,\n",
+      "  \"outputType\": null,\n",
+      "  \"referencedAppId\": null\n",
+      "}"
+    );
+
+    assert_eq!(written.trim(), expected);
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_get_with_invalid_id_it_should_return_usage_error() {
+    let mock_client = MockClient::default();
+
+    let command = FieldsCommand::Get { field_id: 0 };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(
+      result,
+      Err(CliError::usage("field_id must be greater than 0."))
+    );
+    assert!(buffer.is_empty());
+    assert_eq!(*mock_client.get_field_id.lock().unwrap(), None);
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_get_fails_it_should_return_mapped_cli_error() {
+    let mock_client = MockClient {
+      get_field_result: Err(OnspringError::Api {
+        status_code: 404,
+        message: "Field not found".to_string(),
+      }),
+      ..Default::default()
+    };
+
+    let command = FieldsCommand::Get { field_id: 123 };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(
+      result,
+      Err(CliError::runtime("API request failed (404): Field not found"))
+    );
+    assert!(buffer.is_empty());
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_batch_get_succeeds_it_should_write_collection_output() {
+    let mock_client = MockClient {
+      batch_get_fields_result: Ok(CollectionResponse {
+        count: Some(2),
+        items: Some(vec![
+          test_field(1, 10, "Field 1"),
+          test_field(2, 10, "Field 2"),
+        ]),
+      }),
+      ..Default::default()
+    };
+
+    let command = FieldsCommand::BatchGet { ids: vec![1, 2] };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(result, Ok(()));
+
+    let written = String::from_utf8(buffer).unwrap();
+
+    assert_eq!(
+      written.trim(),
+      r#"{"count":2,"items":[{"id":1,"appId":10,"name":"Field 1","type":"Text","status":"Enabled","isRequired":false,"isUnique":false,"multiplicity":null,"listId":null,"values":null,"outputType":null,"referencedAppId":null},{"id":2,"appId":10,"name":"Field 2","type":"Text","status":"Enabled","isRequired":false,"isUnique":false,"multiplicity":null,"listId":null,"values":null,"outputType":null,"referencedAppId":null}]}"#
+    );
+    assert_eq!(
+      *mock_client.batch_get_fields_ids.lock().unwrap(),
+      Some(vec![1, 2])
+    );
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_batch_get_succeeds_pretty_it_should_write_pretty_json() {
+    let mock_client = MockClient {
+      batch_get_fields_result: Ok(CollectionResponse {
+        count: Some(1),
+        items: Some(vec![test_field(1, 10, "Field 1")]),
+      }),
+      ..Default::default()
+    };
+
+    let command = FieldsCommand::BatchGet { ids: vec![1] };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, true).await;
+
+    assert_eq!(result, Ok(()));
+
+    let written = String::from_utf8(buffer).unwrap();
+
+    let expected = concat!(
+      "{\n",
+      "  \"count\": 1,\n",
+      "  \"items\": [\n",
+      "    {\n",
+      "      \"id\": 1,\n",
+      "      \"appId\": 10,\n",
+      "      \"name\": \"Field 1\",\n",
+      "      \"type\": \"Text\",\n",
+      "      \"status\": \"Enabled\",\n",
+      "      \"isRequired\": false,\n",
+      "      \"isUnique\": false,\n",
+      "      \"multiplicity\": null,\n",
+      "      \"listId\": null,\n",
+      "      \"values\": null,\n",
+      "      \"outputType\": null,\n",
+      "      \"referencedAppId\": null\n",
+      "    }\n",
+      "  ]\n",
+      "}"
+    );
+
+    assert_eq!(written.trim(), expected);
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_batch_get_with_empty_ids_it_should_return_usage_error() {
+    let mock_client = MockClient::default();
+
+    let command = FieldsCommand::BatchGet { ids: vec![] };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(result, Err(CliError::usage("ids cannot be empty.")));
+    assert!(buffer.is_empty());
+    assert_eq!(*mock_client.batch_get_fields_ids.lock().unwrap(), None);
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_batch_get_with_invalid_ids_it_should_return_usage_error() {
+    let mock_client = MockClient::default();
+
+    let command = FieldsCommand::BatchGet {
+      ids: vec![1, 0, 2],
+    };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(
+      result,
+      Err(CliError::usage("ids must only contain values > 0."))
+    );
+    assert!(buffer.is_empty());
+    assert_eq!(*mock_client.batch_get_fields_ids.lock().unwrap(), None);
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_batch_get_with_too_many_ids_it_should_return_usage_error() {
+    let mock_client = MockClient::default();
+
+    let command = FieldsCommand::BatchGet {
+      ids: vec![1; 101],
+    };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(
+      result,
+      Err(CliError::usage(
+        "ids cannot contain more than 100 values."
+      ))
+    );
+    assert!(buffer.is_empty());
+    assert_eq!(*mock_client.batch_get_fields_ids.lock().unwrap(), None);
+  }
+
+  #[tokio::test]
+  async fn handle_when_fields_batch_get_fails_it_should_return_mapped_cli_error() {
+    let mock_client = MockClient {
+      batch_get_fields_result: Err(OnspringError::Api {
+        status_code: 500,
+        message: "".to_string(),
+      }),
+      ..Default::default()
+    };
+
+    let command = FieldsCommand::BatchGet { ids: vec![1, 2] };
+    let mut buffer = Vec::new();
+
+    let result = handle(&command, &mock_client, &mut buffer, false).await;
+
+    assert_eq!(
+      result,
+      Err(CliError::runtime("API request failed with status 500."))
+    );
+    assert!(buffer.is_empty());
+  }
+}
+

src/commands/mod.rs

@@ -1,5 +1,6 @@
 pub mod apps;
 pub mod ping;
+pub mod fields;
 
 use std::io::Write;
 
@@ -15,5 +16,6 @@ pub async fn handle<C: OnspringRunner, W: Write>(
   match &cli.command {
     Command::Ping => ping::handle(client, writer, cli.pretty).await,
     Command::Apps { command } => apps::handle(command, client, writer, cli.pretty).await,
-  }
+    Command::Fields { command } => fields::handle(command, client, writer, cli.pretty).await,
+}
 }

src/output.rs

@@ -1,7 +1,10 @@
 use std::io::Write;
 
-use onspring::{App, CollectionResponse, PagedResponse};
+use onspring::{
+  App, CollectionResponse, Field, FormulaOutputType, ListFieldValue, Multiplicity, PagedResponse,
+};
 use serde::Serialize;
+use uuid::Uuid;
 
 use crate::{CliError, CliResult};
 
@@ -88,6 +91,67 @@ impl From<App> for AppOutput {
   }
 }
 
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ListFieldValueOutput {
+  pub id: Uuid,
+  pub name: String,
+  pub sort_order: i32,
+  pub numeric_value: Option<f64>,
+  pub color: Option<String>,
+}
+
+impl From<ListFieldValue> for ListFieldValueOutput {
+  fn from(value: ListFieldValue) -> Self {
+    Self {
+      id: value.id,
+      name: value.name,
+      sort_order: value.sort_order,
+      numeric_value: value.numeric_value,
+      color: value.color,
+    }
+  }
+}
+
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct FieldOutput {
+  pub id: i32,
+  pub app_id: i32,
+  pub name: Option<String>,
+  #[serde(rename = "type")]
+  pub field_type: Option<String>,
+  pub status: Option<String>,
+  pub is_required: bool,
+  pub is_unique: bool,
+  pub multiplicity: Option<Multiplicity>,
+  pub list_id: Option<i32>,
+  pub values: Option<Vec<ListFieldValueOutput>>,
+  pub output_type: Option<FormulaOutputType>,
+  pub referenced_app_id: Option<i32>,
+}
+
+impl From<Field> for FieldOutput {
+  fn from(value: Field) -> Self {
+    Self {
+      id: value.id,
+      app_id: value.app_id,
+      name: value.name,
+      field_type: value.field_type,
+      status: value.status,
+      is_required: value.is_required,
+      is_unique: value.is_unique,
+      multiplicity: value.multiplicity,
+      list_id: value.list_id,
+      values: value
+        .values
+        .map(|values| values.into_iter().map(ListFieldValueOutput::from).collect()),
+      output_type: value.output_type,
+      referenced_app_id: value.referenced_app_id,
+    }
+  }
+}
+
 pub fn render_json<T: Serialize>(value: &T, pretty: bool) -> CliResult<String> {
   if pretty {
     serde_json::to_string_pretty(value).map_err(|_| CliError::runtime("Failed to serialize output"))