[WIP] Add a script for porting data to the new models

src/server.js

@@ -119,7 +119,7 @@ app.get('*', async (req, res, next) => {
       },
       // Sending Material-UI theme through context
       muiTheme,
-      //send apollo client in the context
+      // send apollo client in the context
 
     };
 

tools/port_script/README.md

@@ -0,0 +1,200 @@
+# Portal
+*Port your MySQL data from old schema to the new schema with just a
+configuration file.*
+
+
+## How to
+- Create a `config.js` file which exports an object with rules and database
+config.
+- `npm install`
+- `node index.js`
+
+
+
+## Configuration
+`config.js` must export an object with `host`, `user`, `password`, `db` and
+`rules`. See below for details.
+
+### host [String]
+- Host for database
+
+### user [String]
+- User for database
+
+### password [String]
+- Password for the database
+
+### db [Object]
+- Must contain `source` and `destination` pairs with database names
+
+
+---
+### rules [Array]
+- Contains the rules for porting
+- One rule for each target table
+- Example:
+    ```javascript
+    rules: [ {}, {}, ... , {} ]
+    ```
+
+#### rules[i].table [Object]
+- Object with info about target and source tables
+- Must contain: `old` and `new` objects
+    - `new`: String
+    - `old`: String or Object with `union` and `on` pairs
+- See [old](#rulesitablesold-string-or-object) below for details
+- Example:
+    ```javascript
+    table: {
+        new: 'NEW_TABLE', 
+        old: 'OLD_TABLE'
+    }
+    ```
+
+#### rules[i].fields [Object]
+- Object with `target_attribute`s as keys and `source_attribute`s or other rules
+as values
+- See [fields](#rulesifields-object) below for details
+- Example:
+    ```javascript
+    fields: {
+        user: 'login', 
+        password: 'pass'
+    }
+    ```
+    This SELECTs `login` and `pass` fields from old table and puts in `user` and
+    `pass` of the new table, respectively
+
+#### rules[i].query [String]
+- A MySQL query to run instead of target and source pairs
+- If found, `table` and `fields` objects are ignored
+- Example:
+    ```javascript
+    query: 'INSERT INTO table (user, password) VALUES ("bits", "goa_ftw!");'
+    ```
+    Runs the query as it is
+
+#### rules[i].skip [Boolean]
+- If `true`, the rule is skipped
+- Example:
+    ```javascript
+    rules: [ { skip: true, ... }, {}, {} ]
+    ```
+    This rule is skipped regardless of anything else
+
+
+
+---
+### rules[i].tables.old [String] or [Object]
+- Must be either a string with table name
+- Or an object with `union` and `on`
+    - `union` must be an array with table names
+    - `on` must be a MySQL condition
+- Example:
+    ```javascript
+    old: {
+        union: ['t1', 't2', 't3'],
+        on: 't1.id = t2.id AND t2.id = t3.id'
+    }
+    ```
+    Inner joins the tables with common `id`
+
+
+
+---
+### rules[i].fields [Object]
+
+#### fields[0].if [Object]
+- Evaluates an if condition and enters data accordingly
+- Must contain `condition`, `pass` and `fail`
+- See [condition](#ifcondition) below for details
+- Example:
+    ```javascript
+    if: {
+        condition: {
+            eval: {}
+        },
+        pass: 'login',
+        fail: {
+            value: 'some other'
+        }
+    }
+    ```
+    Checks if `login` attribute of old table is equal to "bits". If yes, puts
+    `login` of old table in the new table else puts a string "some other"
+
+#### fields[0].switch [Object]
+- Evaluates switch condition and enters data accordingly
+- Must contain `condition`, `cases`
+- `cases` must be an object of key-value pairs
+- Example:
+    ```javascript
+    switch: {
+        condition: 'login_type',
+        cases: [
+            { type1: { value: '1' } },
+            { type2: { value: '2' } },
+            { other: 'login_type' }
+        ]
+    }
+    ```
+    If `login_type` equals "type1" put a string "1" or if "type2" put a string
+    "2" or if "other" put the value of `login_type` attribute of old table
+
+#### fields[0].value [String]
+- Any field with `value` will be put as value itself rather than getting it
+from the source table
+- Example:
+    ```javascript
+    user: { value: 'some value' }
+    ```
+    Puts the string "some value" in `user` attribute of the new table
+
+
+
+---
+### if.condition
+#### rules[i].fields[j].if.condition [Object]
+- Must contain `eval` or `or` or `and`
+- `or` or `and` must be an array of objects which must contain `eval`
+- See [eval](#ifconditioneval) below for details
+- Example:
+    ```javascript
+    condition: {
+        or: [
+            { eval: {C1} },
+            { eval: {C2} },
+            {
+                and: [
+                    { eval: {C3} },
+                    { eval: {C4} }
+                ]
+            }
+        ]
+    }
+    ```
+    Is equivalent to `C1 || C2 || (C3 && C4)`
+
+
+
+---
+### if.condition.eval
+#### rules[i].fields[j].switch.condition.eval [Object]
+- Must contain `operator` and (`first_attribute` or `first_value`) and
+(`second_attribute` or `second_value`)
+    - `operator` must be a constant string
+    - `X_attribute` must be an attribute of the table
+    - `X_value` must be a constant string
+- Example:
+    ```javascript
+    condition: {
+        eval:
+            operator: '===',
+            first_attribute: 'login',
+            second_value: 'bits'
+        }
+        pass: { value: '1' },
+        fail: { value: '0' }
+    },
+    ```
+    Put "1" or "0" if `login` of old table is `===` to `bits` of new table