maintain order of columns

Author: ryansmith3136

be/src/api_sql2.rs

@@ -1,5 +1,4 @@
 use std::{
-    collections::HashMap,
     convert::Infallible,
     sync::{Arc, Mutex},
     time::{self, Duration},
@@ -42,10 +41,16 @@ pub struct Request {
     pub query: String,
 }
 
+#[derive(Serialize)]
+pub struct Column {
+    pub name: String,
+    pub pgtype: String,
+}
+
 #[derive(Serialize)]
 pub struct Response {
     pub cursor: query::Cursor,
-    pub columns: HashMap<String, String>,
+    pub columns: Vec<Column>,
     pub rows: Vec<Vec<Value>>,
 }
 
@@ -229,12 +234,15 @@ async fn update_cursor(
     Ok(())
 }
 
-fn get_columns(rows: &[tokio_postgres::Row]) -> HashMap<String, String> {
+fn get_columns(rows: &[tokio_postgres::Row]) -> Vec<Column> {
     rows.first()
         .map(|row| {
             row.columns()
                 .iter()
-                .map(|col| (col.name().to_string(), col.type_().to_string()))
+                .map(|col| Column {
+                    name: col.name().to_string(),
+                    pgtype: col.type_().to_string(),
+                })
                 .collect()
         })
         .unwrap_or_default()

fe/src/static/docs/index-v2.md

@@ -15,7 +15,11 @@ And the response
 ```
 {
   "cursor": {8453: 18479546},
-  "columns": {"from": "bytea", "to": "bytea", "tokens": "numeric"},
+  "columns": [
+    {"name": "from",   "pgtype": "bytea"},
+    {"name": "to",     "pgtype": "bytea"},
+    {"name": "tokens", "pgtype": "numeric"}
+  ],
   "rows":[[
         "0x0000000000000000000000000000000000000000",
         "0xdaabdaac8073a7dabdc96f6909e8476ab4001b34",
@@ -111,8 +115,8 @@ The response will contain a cusror indicating that the chain `8453` was at block
 [
   {
     "cursor": {8453: 42},
-    "columns": {"from": "bytea", "to": "bytea", "value": "numeric"},
-    "rows": [["0xa...", "0xb...", "1"]]
+    "columns": [...],
+    "rows": [[...], ...]
   }
 ]
 ```
@@ -222,7 +226,7 @@ Regardless of the [Request](#request) there is a single response. The response i
 [
   {
     "cursor": {chain_id: max_block_height},
-    "columns": {column_name: column_pg_type},
+    "columns": [{name: string, type: string}],
     "rows": [
       [col1, col2, colN],
       [col1, col2, colN],
@@ -233,7 +237,9 @@ Regardless of the [Request](#request) there is a single response. The response i
 
 The `cursor` object can be copied verbaitum into a subsequent request to query for new data. See [Cursor](#cursor) for more detail.
 
-The `columns` field contains an object mapping the name of the column (derived from the query) to its postgres type (ie `bytea`, `numeric`, `json`, etc.).
+The `columns` field contains an array of objects mapping the name of the column (derived from the query) to its postgres type (ie `bytea`, `numeric`, `json`, etc.).
+
+The order of the `columns` array matches the order of the column data in `rows`.
 
 | ABI Type | JSON Type           |
 |----------|---------------------|