azure_sdk_storage_table 0.30.2

/* Table batch support
* Current limitation:
1. Only support single changeset in a batch request
2. Only allow PUT and GET in changeset
*/
use super::entry_path;
use crate::TableEntry;
use serde::de::DeserializeOwned;
use serde::Serialize;
use serde_json;

const BATCH_BEGIN: &str = r#"--batch_a1e9d677-b28b-435e-a89e-87e6a768a431
Content-Type: multipart/mixed; boundary=changeset_8a28b620-b4bb-458c-a177-0959fb14c977

"#;
const BATCH_END: &str = "--batch_a1e9d677-b28b-435e-a89e-87e6a768a431\n";
const CHANGESET_BEGIN: &str = r#"--changeset_8a28b620-b4bb-458c-a177-0959fb14c977
Content-Type: application/http
Content-Transfer-Encoding: binary

"#;
const CHANGESET_END: &str = "--changeset_8a28b620-b4bb-458c-a177-0959fb14c977--\n";
const UPDATE_HEADER: &str = "Content-Type: application/json\n";
const ACCEPT_HEADER: &str = "Accept: application/json;odata=nometadata\n";
const IF_MATCH_HEADER: &str = "If-Match: *\n";

// RowKey, Payload. Payload None for deletion
pub struct BatchItem<T>(String, Option<TableEntry<T>>)
where
    T: Serialize + DeserializeOwned;

impl<T> BatchItem<T>
where
    T: Serialize + DeserializeOwned,
{
    pub fn new(row_key: String, value: Option<TableEntry<T>>) -> Self {
        BatchItem(row_key, value)
    }
}

pub fn generate_batch_payload<T>(
    uri_prefix: &str,
    table: &str,
    primary_key: &str,
    items: &[BatchItem<T>],
) -> String
where
    T: Serialize + DeserializeOwned,
{
    let mut payload: String = BATCH_BEGIN.to_owned();
    for item in items {
        payload.push_str(CHANGESET_BEGIN);
        payload.push_str(if item.1.is_some() { "PUT" } else { "DELETE" });
        payload.push_str(" ");
        payload.push_str(uri_prefix);
        payload.push_str(entry_path(table, primary_key, item.0.as_str()).as_str());
        payload.push_str(" HTTP/1.1\n");
        payload.push_str(ACCEPT_HEADER);
        if let Some(ref v) = item.1 {
            payload.push_str(UPDATE_HEADER);
            payload.push_str("\n");
            payload.push_str(serde_json::to_string(v).unwrap().as_str());
        } else {
            payload.push_str(IF_MATCH_HEADER);
        }

        payload.push_str("\n");
    }
    payload + CHANGESET_END + BATCH_END
}

#[cfg(test)]
mod test {
    use super::*;

    #[allow(non_snake_case)]
    #[derive(Serialize, Deserialize)]
    struct Entity {
        Rating: i32,
        Text: String,
    }

    #[test]
    fn verify_batch_payload() {
        let expected = r#"--batch_a1e9d677-b28b-435e-a89e-87e6a768a431
Content-Type: multipart/mixed; boundary=changeset_8a28b620-b4bb-458c-a177-0959fb14c977

--changeset_8a28b620-b4bb-458c-a177-0959fb14c977
Content-Type: application/http
Content-Transfer-Encoding: binary

PUT https://myaccount.table.core.windows.net/Blogs(PartitionKey='Channel_17',RowKey='3') HTTP/1.1
Accept: application/json;odata=nometadata
Content-Type: application/json

{"RowKey":"3","PartitionKey":"Channel_17","etag":null,"Rating":9,"Text":".NET..."}
--changeset_8a28b620-b4bb-458c-a177-0959fb14c977
Content-Type: application/http
Content-Transfer-Encoding: binary

PUT https://myaccount.table.core.windows.net/Blogs(PartitionKey='Channel_17',RowKey='3') HTTP/1.1
Accept: application/json;odata=nometadata
Content-Type: application/json

{"RowKey":"3","PartitionKey":"Channel_17","etag":null,"Rating":9,"Text":"PDC 2008..."}
--changeset_8a28b620-b4bb-458c-a177-0959fb14c977
Content-Type: application/http
Content-Transfer-Encoding: binary

DELETE https://myaccount.table.core.windows.net/Blogs(PartitionKey='Channel_17',RowKey='3') HTTP/1.1
Accept: application/json;odata=nometadata
If-Match: *

--changeset_8a28b620-b4bb-458c-a177-0959fb14c977--
--batch_a1e9d677-b28b-435e-a89e-87e6a768a431
"#;

        let items = vec![
            bupdate("Channel_17", "3", 9, ".NET..."),
            bupdate("Channel_17", "3", 9, "PDC 2008..."),
            bdelete("3"),
        ];
        let actual = generate_batch_payload(
            "https://myaccount.table.core.windows.net/",
            "Blogs",
            "Channel_17",
            items.as_slice(),
        );
        assert_eq!(expected, actual);
    }

    fn bupdate(pk: &str, rk: &str, rating: i32, text: &str) -> BatchItem<Entity> {
        BatchItem(
            rk.to_owned(),
            Some(TableEntry {
                partition_key: pk.to_owned(),
                row_key: rk.to_owned(),
                etag: None,
                payload: Entity {
                    Rating: rating,
                    Text: text.to_owned(),
                },
            }),
        )
    }

    fn bdelete(rk: &str) -> BatchItem<Entity> {
        BatchItem(rk.to_owned(), None)
    }
}