Template handler deleting an image
This document covers sample implementations for template POST handler deleting uploaded images using the plug-in image browser. All examples deletes uploaded images from the plug-in sample application table UC_FROALA_SAMPLE_BLOBS.
- Simple
- Default parameters
- Image checksum
- deletes an image using an image id included in image URL
- can be combined with handler browsing images Simple, Default parameters and Custom parameters.
- deletes an image using an image id included in image URL
- can be combined with handler browsing images Simple, Default parameters and Custom parameters.
- secures delete handler with access token passed using default parameters
-
deletes an image using image id encoded as an image URL checksum
-
must be combined with handler uploading an image Image checksum
-
must be combined with handler displaying an image Image checksum
-
must be combined with handler browsing images Image checksum
-
secures delete handler with access token passed using default parameters
Requirements
Handler deleting an uploaded image must meet the following requirements:
- must use POST method
- must be compilable at the run time
- must return 200 HTTP status on success
Handler definition
- Simple
- Default parameters
- Image checksum
| Attribute | Value |
|---|---|
| RESTful Service Module | A custom RESTservice |
| Module Base Path | /customrest/ |
| URI Template | delete-simple |
| Full URL | https://example-domain.com/ords/workspacename/customrest/delete-simple |
| Handler Method | POST |
| Source Type | PL/SQL |
| Mime Types Allowed | Not defined |
| Attribute | Value |
|---|---|
| RESTful Service Module | A custom RESTservice |
| Module Base Path | /customrest/ |
| URI Template | delete-default |
| Full URL | https://example-domain.com/ords/workspacename/customrest/delete-default |
| Handler Method | POST |
| Source Type | PL/SQL |
| Mime Types Allowed | Not defined |
| Attribute | Value |
|---|---|
| RESTful Service Module | A custom RESTservice |
| Module Base Path | /customrest/ |
| URI Template | delete-checksum |
| Full URL | https://example-domain.com/ords/workspacename/customrest/upload-checksum |
| Handler Method | POST |
| Source Type | PL/SQL |
| Mime Types Allowed | Not defined |
Handler parameters
The upload handler doesn't require registering any resource parameters as long as REST specific bind variable :status_code is used to set request HTTP status. The request query parameters are accessibile in the PL/SQL code as bind variables with same name.
Handler Source
The handler deleting uploaded image must be defined as PL/SQL.
- Simple
- Default parameters
- Image checksum
declare
v_image_id varchar2(4000) := :imageId;
begin
begin
if v_image_id is null then
raise_application_error(-20001, 'image id is missing');
end if;
delete from UC_FROALA_SAMPLE_BLOBS where id = v_image_id;
if SQL%ROWCOUNT = 0 then
raise no_data_found;
end if;
:status_code := 200;
exception
when others then
apex_json.open_object;
apex_json.write('error', 'Image not found');
apex_json.write('id', v_image_id, true);
apex_json.close_object;
raise;
end;
exception
when no_data_found then
:status_code := 404;
when others then
:status_code := 500;
end;
declare
v_access_token uc_rte_access_token;
v_image_id varchar2(4000) := :imageId;
/* default query parameters computed on page load */
//highlight-next-line
v_param_accessToken varchar2(32767) := :accessToken;
begin
begin
begin
//highlight-next-line
v_access_token := uc_rte_access_token.create_from_token( v_param_accessToken );
if v_access_token.is_valid = 0 then
raise_application_error(-20001, 'Expired access token');
end if;
exception
when others then
raise_application_error(-20001, 'Invalid access token');
end;
if v_image_id is null then
raise_application_error(-20001, 'image id is missing');
end if;
delete from UC_FROALA_SAMPLE_BLOBS where id = v_image_id;
if SQL%ROWCOUNT = 0 then
raise no_data_found;
end if;
:status_code := 200;
exception
when others then
apex_json.open_object;
apex_json.write('error', 'Image not found');
apex_json.write('id', v_image_id, true);
apex_json.close_object;
raise;
end;
exception
when no_data_found then
:status_code := 404;
when others then
if SQLCODE = -20001 then
:status_code := 403;
else
:status_code := 500;
end if;
end;
declare
v_access_token uc_rte_access_token;
v_image_id varchar2(4000);
v_checksum_decoded varchar2(4000);
/* default query parameters computed on page load */
v_param_accessToken varchar2(32767) := :accessToken;
//highlight-next-line
v_img_param_checksum varchar2(32767) := :checksum;
begin
begin
begin
v_access_token := uc_rte_access_token.create_from_token( v_param_accessToken );
if v_access_token.is_valid = 0 then
raise_application_error(-20001, 'Expired access token');
end if;
exception
when others then
raise_application_error(-20001, 'Invalid access token');
end;
if v_img_param_checksum is null then
raise_application_error(-20001, 'Checksum not included');
end if;
begin
//highlight-next-line
v_checksum_decoded := UC_RTE_ACCESS_TOKEN.decode( v_img_param_checksum );
exception
when others then
raise_application_error(-20001, 'Failed decoding checksum');
end;
//highlight-next-line
v_image_id := apex_string.split(v_checksum_decoded, ',')(2);
delete from UC_FROALA_SAMPLE_BLOBS where id = v_image_id;
if SQL%ROWCOUNT = 0 then
raise no_data_found;
end if;
:status_code := 200;
exception
when others then
apex_json.open_object;
apex_json.write('error', 'Image not found');
apex_json.write('id', v_image_id, true);
apex_json.close_object;
raise;
end
exception
when no_data_found then
:status_code := 404;
when others then
if SQLCODE = -20001 then
:status_code := 403;
else
:status_code := 500;
end if;
end;
Handler Output
When an image deletion is successful, the handler should only set HTTP status code 200.
Error handling
The plug-in display deleting error as APEX inline page notification error with message Image delete failed and message assigned to JSON error property, for example:
Image delete failed: Image not found.