This is div component with some p in it, This div component can control it's css within itself,no matter which page include the div, the css assosiated with the div is there.
```
and css file whose relative url is "css/EA684A9EEB587B07EF746D41882DE073",
```
div#id1 p{line-height:1.5em;margin:0px 2em;color:gray;}
```
Note that css url after "css/" is the MD5 digest value of the generated css entity.
And Noradle automatically add a
This is div component with some p in it, This div component can control it's css within itself,no matter which page include the div, the css assosiated with the div is there.
```
http protocol related
=====================
chunked transfer and buffer flush
----------------------------------
Whether buffer flush is allow if related with "Transfer-Encoding", "Content-MD5", "ETag", "feedback","component css".
GZIP
----------------------------
content-encoding can use gzip compress.
h.content-encoding-gzip will force noradle to return gzipped response.
h.content-encoding-identity force noradle to return original response.
h.content-encoding-auto(default) will see
1. if use content-length header, if length is more than threshold, use gzip
2. if use content-transfer=chunked, if first flush to nodejs is more than threshold, use gzip
Note, if all or first flush output's length is too low, gzip will probably get larger response, so Noradle will avoid gzip in that case.
automatical etag validation 304
--------------------------------
`h.etag_md5_on` will turn on automatic digest comparison to avoid send response entity when the client or intermediate
server have the same entity in its cache. Noradle will compute the digest value of the final produced entity/page,
then set http response header "ETag" to the digest value. When the client request the same servlet,
Noradle will check request header "If-None-Match", if its value is equal to the just generated digest value,
Noradle will response with http 304 response with empty http entity, so the client can just use its cache (validated
fresh), network transfer of response entity is avoided. `h.etag_md5_off` will turn the feature off. If the page
set http status code other than 200, "auto-etag-304" feature will turn off.
last_modified and 304
-----------------------
If all the ingredients of the servlet response is not modified, the response is not modified.
So, check each ingredient's last_modified and update the staged response last_modified by calling `h.last_modified
(date)`, if the final "last_modified" highest value is equal to http request header "if-modified-since",
then you can judge the response will not be a new one, so response with 304 status code and empty entity.
That way, you avoid actually generate the response entity and all the network transfer and processing of it.
`h.last_modified(date)` will record the high-water-mark value of all call's inut parameter value.
So, when get each part's "last_modified", use it to call `h.last_modified`.
After this, call `h.check_if_not_modified_since` to compare with request's "if-modified-since",
if it's really equal or not modified, the API call will response status 304 and jump out servlet execution.
```
procedure last_modified is
begin
h.expires_now;
h.last_modified(trunc(sysdate));
select max(a.last_ddl_time) into tmp.dt from user_objects a;
h.last_modified(tmp.dt);
h.check_if_not_modified_since;
p.h;
src_b.link_proc;
p.p('When this page is accessed, It may return 304 not modified for the entire day until mid-night.');
p.p('But if you modified/compiled some of the schema objeccts, It will detect the change and return the current version');
p.p('The last-modified-time will be max of the 00:00 in the morning or last-ddl-time of the schema objects.');
p.p('You can call h.last_modified multiple times, then call h.header_close, ' || '
the last-modified header will be set the lasted date value of them, ' ||
'So if the page have many parts, you can call h.last_modified for each part''s last modified time.');
p.br;
for i in (select * from user_objects a where a.object_type != 'PACKAGE' order by a.last_ddl_time desc) loop
p.p(t.dt2s(i.last_ddl_time) || ' > ' || i.object_name);
end loop;
end;
```
manual etag
-----------------
Like `h.last_modified` and `h.check_if_not_modified_since` API usage and automatic digest ETag,
you can set your own ETag manually by calling `h.etag(value)`, if http request header "If-None-Match" is same as the
new etag "value", then response will be the same as the client's cached entity. So,
Noradle will jump out of servlet execution and response with 304 status code and empty entity.
mime-type
----------------------------
By default, Noradle servlet will produce "text/html" http response, that's to say,
Noradle will set http response header "Content-Type" to "text/html",
but response entity are simply text entity, you can set "Content-Type" to any mime-type,
If you print table data as a html table, you can set "Content-Type" to "application/vnd.ms-excel",
So browser will treat the response as excel file download.
So you can just produce "text/plain", "text/xml", "text/...".
Call `h.content_type` to set http response entity mime-type
```
procedure content_type
(
mime_type varchar2 := 'text/html',
charset varchar2 := 'UTF-8'
)
```
file download
----------------------------
Call `h.content_disposition_attachment('filename.ext');` to let browser treat response entity as file download.
For example, download a excel sheet whose data is from database table.
```
procedure excel is
cursor c_packages is
select * from user_objects a where a.object_type = 'PACKAGE' order by a.object_name asc;
begin
h.content_disposition_attachment('test.xls');
p.doc_type('5');
p.h;
p.table_open(rules => 'all', cellspacing => 0, cellpadding => 5, ac => st('#border:1px solid silver;'));
p.caption('table example');
p.thead_open;
p.tr(p.ths(st('package name', 'created')));
p.thead_close;
p.tbody_open;
for i in c_packages loop
p.tr_open;
p.td(i.object_name);
p.td(t.d2s(i.created));
p.tr_close;
end loop;
p.tbody_close;
p.table_close;
end;
```
file upload
----------------------------
### oracle can specify where the upload file will be saved
1) full path including directory and filename with ext.
```