spreadsheet-to-json: Convert Spreadsheets and CSV files to jSON

This library crate provides the core functions to convert common spreadsheet and CSV files into JSON or JSONL (JSON Lines) either directly or asynchronously.

It relies on the Calamine and CSV library crates to process files, the tokio crate for asynchronous operations and naturally serde and serde_json serialization libraries.

It supports the following formats:

• Excel 2007 (.xlsx)
• Excel 97-2004 (.xls)
• OpenDocument Spreadsheets (.ods) compatible with LibreOffice
• CSV: comma separated files
• TSV: Tab-separated files

Features

• Blazingly fast
• Can export to standard JSON or to JSON lines when writing large files

• Formula cells are read as calculated values
• Can identify and convert both Excel's 1900 datetime format and standard ISO format as used in OpenDocument Spreadsheet

• Can identify numeric fields formatted as text and convert them to integers or floats.
• Can identify truthy text or number cells and convert them to booleans
• Can save large files asynchronously

To do

Full explanation of options to come.

Alpha warning

This crate is still alpha and likely to undergo breaking changes as it's part of larger data import project. I do not expect a stable version before mid January when it has been battle-tested.

• 0.1.2 All public error types now use the GenericError error type

Examples

The main implementation is my unpublished Spreadsheet to JSON CLI crate,

Simple immediate parsing. This must be called in an async function.

use spreadsheet_to_json::*;
use spreadsheet_to_json::tokio;

#[tokio:main]
async fn main() -> Result((), Error) {
  let opts = Opts::new("path/to/spreadsheet.xslx")->set_sheet_index(1);
  let result = render_spreadsheet_direct(&opts).await;
  let json_value = match result {
    Err(msg_code) => json!{ { "error": true, "key": msg_code.to_string() },
    Ok(data_set) => data_set.to_json() // full result set
  };
  println!("{}", json_value);
}

Asynchronous parsing. This must be called in an async function.

use spreadsheet_to_json::*;
use spreadsheet_to_json::tokio;

#[tokio:main]
async fn main() -> Result((), GenericError) {
  let opts = Opts::new("path/to/spreadsheet.xlsx")->read_mode_async();
  let dataset_id = db_dataset_id(&opts);

  let callback = move |row: IndexMap<String, Value>| -> Result<(), Error> {
    save_data_row(row, &connection, dataset_id)
  };

  let result = render_spreadsheet_core(&opts, Some(callback), Some(dataset_id)).await;
  let result_set = match result {
      Err(msg_code) => json!{ { "error": true, "key": msg_code.to_string() },
      Ok(data_set) => data_set.to_json() // full result set
  };
  println!("{}", result_set);
}

// Save function called in a closure for each row with a database connection and data_id from the outer scope
fn save_data_row(row: IndexMap<String, Value>, connection: PgConnection, data_id: u32) -> Result((), GenericError) {
    let mut row_struct = CustomTableStruct {
    id: None,
    data_id: data_id, // or whatever ID setting logic you have
    field1: None,
    field2: None,
    // ... set other fields to None or default values
  };
  
  for (key, value) in row {
    match key.as_str() {
        "field1" => {
            if let Value::String(s) = value {
                row_struct.field1 = Some(s.clone());
            }
        },
        "field2" => {
            if let Value::Number(n) = value {
                if let Some(i) = n.as_i64() {
                    row_struct.field2 = Some(i as i32);
                }
            }
        },
        // Add other field mappings here
        _ => {} // Ignore unknown keys
    }
  }
  diesel::insert_into("data_rows")
  .values(&row_struct)
  .execute(connection),map_error(|_| GenericError("database_error"));
  Ok()
}