jim hamblen
Live RSS news feeds are displayed on a basic text LCD See http://mbed.org/users/4180_1/notebook/news-lcd-display/
Dependencies: NetServices TextLCD mbed spxml HTTPClient_ToBeRemoved
main.cpp@0:582c6436e759, 2012-04-24 (annotated)
- Committer:
- 4180_1
- Date:
- Tue Apr 24 02:27:43 2012 +0000
- Revision:
- 0:582c6436e759
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| 4180_1 | 0:582c6436e759 | 1 | #include "mbed.h" |
| 4180_1 | 0:582c6436e759 | 2 | #include "EthernetNetIf.h" |
| 4180_1 | 0:582c6436e759 | 3 | #include "HTTPClient.h" |
| 4180_1 | 0:582c6436e759 | 4 | #include "TextLCD.h" |
| 4180_1 | 0:582c6436e759 | 5 | //CNN Tech News RSS Feed - get web page with XML |
| 4180_1 | 0:582c6436e759 | 6 | // displays titles on LCD from XML "<title>....title text...</title>" |
| 4180_1 | 0:582c6436e759 | 7 | TextLCD lcd(p15, p16, p17, p18, p19, p20); // rs, e, d0-d3 |
| 4180_1 | 0:582c6436e759 | 8 | EthernetNetIf eth; |
| 4180_1 | 0:582c6436e759 | 9 | HTTPClient http; |
| 4180_1 | 0:582c6436e759 | 10 | HTTPResult result; |
| 4180_1 | 0:582c6436e759 | 11 | bool completed = false; |
| 4180_1 | 0:582c6436e759 | 12 | void request_callback(HTTPResult r) { |
| 4180_1 | 0:582c6436e759 | 13 | result = r; |
| 4180_1 | 0:582c6436e759 | 14 | completed = true; |
| 4180_1 | 0:582c6436e759 | 15 | } |
| 4180_1 | 0:582c6436e759 | 16 | |
| 4180_1 | 0:582c6436e759 | 17 | int main() { |
| 4180_1 | 0:582c6436e759 | 18 | char *tstartXML = "<title>"; //RSS XML start title |
| 4180_1 | 0:582c6436e759 | 19 | char *tendXML ="</title>"; //RSS XML end title |
| 4180_1 | 0:582c6436e759 | 20 | char *tsptr; |
| 4180_1 | 0:582c6436e759 | 21 | char *teptr; |
| 4180_1 | 0:582c6436e759 | 22 | int i=0,j=0; |
| 4180_1 | 0:582c6436e759 | 23 | // the eth and HTTP code has be taken directly from the HTTPStream documentation page |
| 4180_1 | 0:582c6436e759 | 24 | // see http://mbed.org/cookbook/HTTP-Client-Data-Containers |
| 4180_1 | 0:582c6436e759 | 25 | lcd.cls(); |
| 4180_1 | 0:582c6436e759 | 26 | lcd.printf("net setup"); |
| 4180_1 | 0:582c6436e759 | 27 | EthernetErr ethErr = eth.setup(); |
| 4180_1 | 0:582c6436e759 | 28 | if (ethErr) { |
| 4180_1 | 0:582c6436e759 | 29 | lcd.printf("\n\r net error"); |
| 4180_1 | 0:582c6436e759 | 30 | return -1; |
| 4180_1 | 0:582c6436e759 | 31 | } |
| 4180_1 | 0:582c6436e759 | 32 | lcd.printf("\n\r net ok"); |
| 4180_1 | 0:582c6436e759 | 33 | HTTPStream stream; |
| 4180_1 | 0:582c6436e759 | 34 | char BigBuf[2048 + 1] = {0}; |
| 4180_1 | 0:582c6436e759 | 35 | stream.readNext((byte*)BigBuf, 2048); //Point to buffer for the first read |
| 4180_1 | 0:582c6436e759 | 36 | //CNN Tech News RSS Feed - get web page with XML |
| 4180_1 | 0:582c6436e759 | 37 | HTTPResult r = http.get("HTTP://rss.cnn.com/rss/cnn_tech.rss", &stream, request_callback); |
| 4180_1 | 0:582c6436e759 | 38 | while (!completed) { |
| 4180_1 | 0:582c6436e759 | 39 | Net::poll(); // Polls the Networking stack |
| 4180_1 | 0:582c6436e759 | 40 | if (stream.readable()) { // check for end of file |
| 4180_1 | 0:582c6436e759 | 41 | BigBuf[stream.readLen()] = 0; // Transform this buffer in a zero-terminated char* string |
| 4180_1 | 0:582c6436e759 | 42 | tsptr = BigBuf; |
| 4180_1 | 0:582c6436e759 | 43 | // displays titles on LCD from XML "<title>....title text...</title>" |
| 4180_1 | 0:582c6436e759 | 44 | do { |
| 4180_1 | 0:582c6436e759 | 45 | tsptr = strstr(tsptr,tstartXML); // find <title> in string - NULL if not |
| 4180_1 | 0:582c6436e759 | 46 | teptr = strstr(tsptr,tendXML); // find <\title> in string - NULL if not |
| 4180_1 | 0:582c6436e759 | 47 | if (tsptr!=NULL) tsptr = tsptr + strlen(tstartXML);// move to char after "<title>" |
| 4180_1 | 0:582c6436e759 | 48 | if ((tsptr!=NULL)&&(teptr!=NULL)) { |
| 4180_1 | 0:582c6436e759 | 49 | i=0; |
| 4180_1 | 0:582c6436e759 | 50 | // loop to scroll characters slowly across LCD |
| 4180_1 | 0:582c6436e759 | 51 | for (j=0; (j+15)<(strlen(tsptr)-strlen(teptr)); j++) { |
| 4180_1 | 0:582c6436e759 | 52 | lcd.cls(); // clear screen before writing a new line |
| 4180_1 | 0:582c6436e759 | 53 | // loop to output a line on the LCD |
| 4180_1 | 0:582c6436e759 | 54 | for (i=0; ((i<16)&&(tsptr[i+j-1] != '<')); i++) { |
| 4180_1 | 0:582c6436e759 | 55 | lcd.putc(tsptr[i+j]); |
| 4180_1 | 0:582c6436e759 | 56 | } |
| 4180_1 | 0:582c6436e759 | 57 | if (j==0) wait(1.2); //add first line delays for scroll timing |
| 4180_1 | 0:582c6436e759 | 58 | wait(.2); //delay for charcter scroll timing |
| 4180_1 | 0:582c6436e759 | 59 | } |
| 4180_1 | 0:582c6436e759 | 60 | wait(.4); |
| 4180_1 | 0:582c6436e759 | 61 | lcd.cls(); //clear LCD between news items |
| 4180_1 | 0:582c6436e759 | 62 | wait(.2); |
| 4180_1 | 0:582c6436e759 | 63 | } |
| 4180_1 | 0:582c6436e759 | 64 | } while (tsptr!=NULL); // No more "<title>"s in BigBuf to display |
| 4180_1 | 0:582c6436e759 | 65 | stream.readNext((byte*)BigBuf, 2048); //Buffer has been read, now we can put more data in it |
| 4180_1 | 0:582c6436e759 | 66 | } |
| 4180_1 | 0:582c6436e759 | 67 | } |
| 4180_1 | 0:582c6436e759 | 68 | lcd.cls(); |
| 4180_1 | 0:582c6436e759 | 69 | if (result == HTTP_OK) { |
| 4180_1 | 0:582c6436e759 | 70 | lcd.cls(); |
| 4180_1 | 0:582c6436e759 | 71 | lcd.printf(" Read complete\n\r"); |
| 4180_1 | 0:582c6436e759 | 72 | } else { |
| 4180_1 | 0:582c6436e759 | 73 | lcd. printf(" Error %d\n", result); |
| 4180_1 | 0:582c6436e759 | 74 | return -1; |
| 4180_1 | 0:582c6436e759 | 75 | } |
| 4180_1 | 0:582c6436e759 | 76 | } |