better project structure

src/admin/form.rs

@@ -0,0 +1,87 @@
+//! Multipart form handling shared by the product and category admin forms.
+//!
+//! Both forms submit a mix of text fields and an optional `image` file part;
+//! this collects them into an easy-to-query [`MultipartForm`] and stores any
+//! uploaded image through the configured storage driver.
+
+use std::collections::HashMap;
+
+use axum::extract::Multipart;
+use loco_rs::prelude::*;
+
+use crate::media::{detect_image_extension, store_upload, IMAGE_MAX_BYTES, IMAGE_STORAGE_DIR};
+
+fn normalize_empty(value: Option<String>) -> Option<String> {
+    value.and_then(|value| {
+        let value = value.trim().to_string();
+        (!value.is_empty()).then_some(value)
+    })
+}
+
+/// Collected multipart form: text fields keyed by name, plus the raw bytes of
+/// an `image` file part if one was uploaded (an empty file input is ignored).
+pub(crate) struct MultipartForm {
+    fields: HashMap<String, String>,
+    pub(crate) image: Option<Vec<u8>>,
+}
+
+impl MultipartForm {
+    /// Trimmed value of a text field, `None` when missing or blank.
+    pub(crate) fn text(&self, key: &str) -> Option<String> {
+        normalize_empty(self.fields.get(key).cloned())
+    }
+
+    /// Whether a checkbox-style field is checked.
+    pub(crate) fn checked(&self, key: &str) -> bool {
+        matches!(
+            self.fields.get(key).map(String::as_str),
+            Some("on" | "true" | "1")
+        )
+    }
+}
+
+pub(crate) async fn read_multipart_form(mut multipart: Multipart) -> Result<MultipartForm> {
+    let mut fields = HashMap::new();
+    let mut image = None;
+
+    while let Some(mut field) = multipart
+        .next_field()
+        .await
+        .map_err(|err| Error::BadRequest(format!("invalid multipart data: {err}")))?
+    {
+        let name = field.name().unwrap_or("").to_string();
+        if name == "image" {
+            let mut data = Vec::new();
+            while let Some(chunk) = field
+                .chunk()
+                .await
+                .map_err(|err| Error::BadRequest(format!("invalid multipart chunk: {err}")))?
+            {
+                data.extend_from_slice(&chunk);
+                if data.len() > IMAGE_MAX_BYTES {
+                    return Err(Error::BadRequest(format!(
+                        "image is larger than {} MB",
+                        IMAGE_MAX_BYTES / 1024 / 1024
+                    )));
+                }
+            }
+            if !data.is_empty() {
+                image = Some(data);
+            }
+        } else {
+            let value = field
+                .text()
+                .await
+                .map_err(|err| Error::BadRequest(format!("invalid multipart field: {err}")))?;
+            fields.insert(name, value);
+        }
+    }
+
+    Ok(MultipartForm { fields, image })
+}
+
+/// Store an uploaded image's bytes and return its generated filename.
+pub(crate) async fn store_image(ctx: &AppContext, data: Vec<u8>) -> Result<String> {
+    let extension = detect_image_extension(&data)?;
+    store_upload(ctx, IMAGE_STORAGE_DIR, extension, data).await
+}